Newton Jumps the Shark

The telescope made Newton famous and brought him that increase of his acquaintance that he feared. Far from rejoicing in the questions and challenges that other scientists - notably Hooke - posed to his theory of light, he was irritated by them and responded impatiently and rudely. Newton, who had been elected a fellow of the Royal Society a year earlier, now (in 1673) threatened to withdraw his membership.

With his mathematical writings it was the same story. Others questioned his methods, and rather than treating these questions as part of the normal scientific give and take, Newton got offended and claimed he would "let what I write ly by till I am out of ye way." Indeed, he said he was going to put philosophy aside and "prosecute some other subjects."

What were these other subjects that had grabbed Newton's attention? They were two: alchemy and theology.

Newton's obsession with alchemy, which lasted many more years than did his brief fascination with mathematics, seems strange to us from the viewpoint of the 21st century. It helps to remember that two of his known correspondents on the subject were that master experimentalist Robert Boyle and the arch empiricist John Locke. In 1672, the idea that chemical substances contained spiritual principles and could, under the right circumstances, vegetate and grow, was not so obviously unscientific as it appears today.

Newton obtained his alchemical writings from a secret network about which we know very little today. Many alchemists hid their names, publishing under pseudonyms. Newton referred to them in his writings by initials alone. Newton amassed a vast collection of alchemical manuscripts over a period of more than 30 years.

He was not just reading about alchemy, though: he built his own laboratory, with an impressive variety of furnaces to produce the various levels of heat he needed for his experiments. In spite of the length of time he spent on these investigations and his copious notebooks, it is not so clear what his goal in all this was. Producing gold appears very rarely as a target. A more definite goal was something he called "sophic sal ammoniac." At one point in his notes he becomes very excited at the idea that he has succeeded in producing this mysterious substance.

I perfected the ideal solution. That is, two equal salts carry up Saturn. Then he carries up the stone and joined with malleable Jupiter also makes X [a star symbol I can't reproduce here] and that in such proportion that Jupiter grasps the scepter. Then the eagle carries Jupiter up. Hence Saturn can be combined without salts in the desired proportions so that fire does not predominate. At last mercury sublimate and sophic sal ammoniac shatter the helmet and the menstruum carries everything up.

The passage gives you a feel for what alchemical writing was like: coded, allusive, and mysterious. Surely, a man of Newton's intelligence and skills would not have wasted his time for three decades on complete nonsense! To him, it must have meant something: what that was, we can no longer recover.

Newton the Odd Duck

One might have expected that Isaac Newton, country bumpkin newly become scholar, would have been eager to publish his discoveries in science and mathematics and make a name for himself.

One would have been wrong.

Though he wrote up his discoveries in essays in his notebooks, and on occasion seemed to be writing a paper for publication, he avoided disseminating his work to an astonishing, even incomprehensible degree. His invention of infinitesimal methods (calculus), his essay on "The lawes of Motion," his optical experiments, all languished in his desk drawers.

He seems, indeed, to have had little human contact of any kind apart from his long-time roommate, John Wickins, and the Lucasian Professor of Mathematics, Isaac Barrow. Years later, Wickins described Newton as someone so obsessed with his studies that he often forgot to eat and sleep. On the rare occasions he went to the public dining-hall, he went with "shooes down at Heels, Stockins unty'd, surplice on, & his Head scarcely comb'd." He never, as an adult, had a romantic relationship with a woman.

He was, in short, a nerd.

One might deduce from his lack of interest in publishing his work that he was simply uninterested in fame or in other people's opinions of him.

One would be wrong.

The incident that finally led him to put some of his work out in public view was the publication, in 1668, of a mathematical book of Nicholas Mercator that included the infinite series for log(1 + x). Newton suddenly saw himself being scooped on all his wonderful mathematical discoveries, and hastily put together a treatise on infinite series. He passed this on to Barrow, but forbade him to send it to anyone else. Finally, Newton gave Barrow permission to send the paper on to John Collins, a man who made it his business to facilitate communication among British mathematicians. Only when Collins reacted favorably did Newton allow the paper to be disseminated further. But when Collins and Barrow wanted to publish it as an appendix to Barrow's forthcoming book on optics, Newton drew back.

Thus a pattern was set. Newton would drop hints about his discoveries, begin to write them up, then put them aside and refuse to publish them. But let a challenger appear, and Newton would rush forward to claim priority. So by his own refusal to publish he became embroiled in priority disputes: notably with Leibniz over the calculus and with Hooke over the law of gravity.

Collins and Barrow continued to encourage Newton's mathematical investigations. Barrow asked him to annotate a Latin translation of a Dutch book on algebra, and Collins asked him to derive a formula for calculating the interest on an annuity. Collins wanted to publish Newton's formula, and Newton agreed, "soe it bee without my name on it. For I see not what there is desirable in publick esteeme, were I able to acquire and maintain it. It would perhaps increase my acquaintance, ye thing which I cheifly study to decline." 

Newton's claim to be uninterested in the British pastime of "increasing one's acquaintance," i.e., social climbing, is rather ironic, knowing as we do how tenaciously he was to grasp at fame in the not too distant future.

His mathematical work began to attract notice, but what really brought him to prominence was his invention of the reflecting telescope. Around 1669, his optical studies led him to realize that telescopes built of lenses will always suffer from a blurring due to the fact that different colors of light refract differently. A telescope built with mirrors instead of lenses would not suffer this drawback. Newton's 6-inch long reflector was more powerful than a 6 foot refractor.

The Royal Society, England's scientific society, got wind of the telescope, and, in 1671, Barrow brought it to them. Newton was swept up in a flood of adulation, and sent the Royal Society a paper on his optical investigations. The telescope and the paper brought Newton, finally, into the international scientific limelight.

Faculties of Other Experiences

"But I have wondered if there might not be colleges and faculties of other experiences than yours, and whether even now, in the far corners of other continents, powers not yours are being brought to fruition." Charles Williams, Shadows of Ecstasy

The more I think about it, the more I am convinced that those three guys are right.

In Terry Pratchett's A Hat Full of Sky, a witch's cabin is inhabited by a invisible creature the witch calls Oswald. At least, she thinks it is. Whenever she puts a fork in amongst the spoons, the drawer rattles, pops open, and the fork leaps over into the correct spot.  If something gets dropped, a dustpan and brush appear and magically sweep things up. If Miss Level (the witch) mixes some salt together with the pepper, Oswald will happily (so she surmises) spend an afternoon sorting the salt grains from among the pepper.

Given the phenomenon Pratchett describes, it's hard to think of any hypothesis that would cover it, other than that of an invisible, intelligent agent. If we had numerous instances, well documented, of such occurrences, we would have to conclude that incorporeal intelligent beings exist.

But we don't.

In Williams's story, there is an uprising of Africans who wield powers not understood by European science. They are able to prolong life far beyond the normal human lifespan. They can exert a sort of mind control on others.

In Williams's day, it might have still seemed possible that some remote group in Africa had developed an alternate "technology," one based in supernatural rather than natural causes. Today, having made contact with numerous such remote groups all over the world, and having discovered no technologies that make effective use of supernatural forces, it's hard to believe that such skills exist anywhere.

It's not that "colleges and faculties of other experiences" don't exist: nearly all human groups make attempts to manipulate the supernatural forces of their systems of belief. It's just that they don't work: appealing to the supernatural is not an effective way of getting things done.

OK, I usually don't like to brag, but it's not often that you get props for being a bookish nerd. Thanks to aNadder, I discovered the BBCs list of 100 books: you're supposed to bold them if you've read them and italicize them if you've partially read them. Here goes:

1. The Lord of the Rings, JRR Tolkien
2. Pride and Prejudice, Jane Austen
3. His Dark Materials, Philip Pullman
4. The Hitchhiker's Guide to the Galaxy, Douglas Adams
5. Harry Potter and the Goblet of Fire, JK Rowling
6. To Kill a Mockingbird, Harper Lee
7. Winnie the Pooh, AA Milne
8. Nineteen Eighty-Four, George Orwell
9. The Lion, the Witch and the Wardrobe, CS Lewis
10. Jane Eyre, Charlotte Brontë
11. Catch-22, Joseph Heller
12. Wuthering Heights, Emily Brontë
13. Birdsong, Sebastian Faulks
14. Rebecca, Daphne du Maurier
15. The Catcher in the Rye, JD Salinger
16. The Wind in the Willows, Kenneth Grahame
17. Great Expectations, Charles Dickens
18. Little Women, Louisa May Alcott
19. Captain Corelli's Mandolin, Louis de Bernieres
20. War and Peace, Leo Tolstoy
21. Gone with the Wind, Margaret Mitchell
22. Harry Potter And The Philosopher's Stone, JK Rowling
23. Harry Potter And The Chamber Of Secrets, JK Rowling
24. Harry Potter And The Prisoner Of Azkaban, JK Rowling
25. The Hobbit, JRR Tolkien
26. Tess Of The D'Urbervilles, Thomas Hardy
27. Middlemarch, George Eliot
28. A Prayer For Owen Meany, John Irving
29. The Grapes Of Wrath, John Steinbeck
30. Alice's Adventures In Wonderland, Lewis Carroll
31. The Story Of Tracy Beaker, Jacqueline Wilson
32. One Hundred Years Of Solitude, Gabriel García Márquez
33. The Pillars Of The Earth, Ken Follett
34. David Copperfield, Charles Dickens
35. Charlie And The Chocolate Factory, Roald Dahl
36. Treasure Island, Robert Louis Stevenson
37. A Town Like Alice, Nevil Shute
38. Persuasion, Jane Austen
39. Dune, Frank Herbert
40. Emma, Jane Austen
41. Anne Of Green Gables, LM Montgomery
42. Watership Down, Richard Adams
43. The Great Gatsby, F Scott Fitzgerald
44. The Count Of Monte Cristo, Alexandre Dumas
45. Brideshead Revisited, Evelyn Waugh
46. Animal Farm, George Orwell
47. A Christmas Carol, Charles Dickens
48. Far From The Madding Crowd, Thomas Hardy
49. Goodnight Mister Tom, Michelle Magorian
50. The Shell Seekers, Rosamunde Pilcher
51. The Secret Garden, Frances Hodgson Burnett
52. Of Mice And Men, John Steinbeck
53. The Stand, Stephen King
54. Anna Karenina, Leo Tolstoy
55. A Suitable Boy, Vikram Seth
56. The BFG, Roald Dahl
57. Swallows And Amazons, Arthur Ransome
58. Black Beauty, Anna Sewell
59. Artemis Fowl, Eoin Colfer
60. Crime And Punishment, Fyodor Dostoyevsky
61. Noughts And Crosses, Malorie Blackman
62. Memoirs Of A Geisha, Arthur Golden
63. A Tale Of Two Cities, Charles Dickens
64. The Thorn Birds, Colleen McCollough
65. Mort, Terry Pratchett
66. The Magic Faraway Tree, Enid Blyton
67. The Magus, John Fowles
68. Good Omens, Terry Pratchett and Neil Gaiman
69. Guards! Guards!, Terry Pratchett
70. Lord Of The Flies, William Golding
71. Perfume, Patrick Süskind
72. The Ragged Trousered Philanthropists, Robert Tressell
73. Night Watch, Terry Pratchett
74. Matilda, Roald Dahl
75. Bridget Jones's Diary, Helen Fielding
76. The Secret History, Donna Tartt
77. The Woman In White, Wilkie Collins
78. Ulysses, James Joyce
79. Bleak House, Charles Dickens
80. Double Act, Jacqueline Wilson
81. The Twits, Roald Dahl
82. I Capture The Castle, Dodie Smith
83. Holes, Louis Sachar
84. Gormenghast, Mervyn Peake
85. The God Of Small Things, Arundhati Roy
86. Vicky Angel, Jacqueline Wilson
87. Brave New World, Aldous Huxley
88. Cold Comfort Farm, Stella Gibbons
89. Magician, Raymond E Feist
90. On The Road, Jack Kerouac
91. The Godfather, Mario Puzo
92. The Clan Of The Cave Bear, Jean M Auel
93. The Colour Of Magic, Terry Pratchett
94. The Alchemist, Paulo Coelho
95. Katherine, Anya Seton
96. Kane And Abel, Jeffrey Archer
97. Love In The Time Of Cholera, Gabriel García Márquez
98. Girls In Love, Jacqueline Wilson
99. The Princess Diaries, Meg Cabot
100. Midnight's Children, Salman Rushdie

This, the actual BBC list, is quite a bit different from aNadder's list. Whoever did the alterations included some whole series (Eg. Harry Potter, His Dark Materials) on the list, which perhaps make sense (as well as making room for some more books). But, while adding The Chronicles of Narnia, they left on THe Lion, the Witch, and the Wardrobe, which is part of The Chronicles of Narnia, so it's a somewhat incoherent list.

There are very few partially-reads - though to be honest I cheated a bit on this, and left out On The Road, which I started but couldn't get past the first few pages. (And this from someone who War and Peace cover to cover. Unabridged, too.) I also left out Gone With the Wind, which I just started yesterday when I was desperate for something to read, and which I have only read about three pages of.

OK, so maybe I should have written "book addict" instead of "bookish nerd"?

Newton as Grad Student

When we left Isaac Newton, he had just graduated from college - "commenced Bachelor of Arts," as the terminology of the day put it - and obtained a scholarship so that he could continue his studies. He had taken no formal courses and passed no exams. He had pursued a course of study completely his own, with, as far as can be told, no formal instruction or even any significant advice from the faculty of Trinity College. He had, nonetheless, managed to master the most advanced mathematics that was in existence, working his way through Descartes's mathematical works page by painstaking page.

Graduation meant little to Newton - he continued his idiosyncratic studies without concern for recognition or advancement. He pressed on, inventing new techniques to push his mathematical understanding further. He developed infinite series that approximated known functions, and used them to calculate those functions to unprecedented accuracy. He invented infinitesimals, that he called "fluxions," and laid the basis for the differential and integral calculus. He even developed a version of what is now known as "the fundamental theorem of calculus": that differentiation and integration are inverse processes; one undoes what the other does. He had far surpassed anything accomplished by any other mathematician in the world. He was completely unknown, 24 years old, and one year past his college commencement.

As suddenly as he had picked up mathematics, he laid it down and turned to other things. He began his studies of optics and of motion. He bought a prism and began studying the properties of colored light. But the plague struck, and Newton fled to the country to his mother's house in Lincolnshire. He had to wait several years before he could obtain a second prism and perform the experiments that would solidify his theory of light.

He turned to the study of motion, and began an investigation of the properties of circular motion. From this investigation he concluded that the acceleration of the Moon about the Earth was related to the acceleration of an object falling near the Earth by the ratio of their distances squared, "pretty nearly." It was about this time (1666) that the famous apple incident occurred, if it occurred at all.

The years 1665-1666 are called Newton's anni mirabiles, his miraculous years, in which he developed his theory of light, of motion, and of the calculus. In fact, he had only begun the work that would, much later, become fully developed theories. But his accomplishments were nonetheless miraculous. As Richard Westfall puts it,

In 1660, a provincial boy ate his heart out for the world of learning .... Six years later, with no help beyond the books he had found for himself, he had made himself the foremost mathematician in Europe and the equal of the foremost natural philosopher.

For similar experiments on the nature of light, Christiaan Huygens was being sought after by the kings of Europe. As yet, no one knew the name of Isaac Newton, nor what he had accomplished.

Exorcize Your Car!

Your car breaks down: who do you go to? The mechanic, who will try to fix a mechanical flaw, or the priest, who will exorcise the car demons?

According to some people, scientists must exclude supernatural explanations on philosophical grounds. This is known as the principle of methodological naturalism. Interestingly, the claim comes both from scientists, who declare it a philosophical prerequisite for doing science, and from religious folks, who see it as a philosophical bias that prevents scientists from ever recognizing supernatural causes.

A recent paper by the philosophical trio of Maarten Boudry, Stefaan Blancke, and Johan Braeckman
suggests that science requires no such bias. Supernatural explanations are not excluded on philosophical grounds; rather, such explanations simply have not worked out in practice. The authors call this view pragmatic methodological naturalism: we look for naturalistic explanations because that type of explanation has been successful in the past. (See also Jerry Coyne's comments on the article here.)

To go back to the car example: I think everyone, whether religious or not, chooses to take the naturalistic route when their car breaks down. It's not a matter of anti-supernatural bias (since the priest does it too, even if he adds a prayer to the procedure), it's just a pragmatic consideration. We have experience with the mechanical approach being successful, as we do not for the exorcism approach. We have reason to believe that we understand pretty well how a car works - or at least the mechanic does - and so we have a theoretical basis on which to expect a naturalistic approach to work. We don't have a similar basis for thinking that getting rid of the car demons will solve the problem. 

I think this is correct: science doesn't need to exclude supernatural explanations from its consideration, it only needs to apply the same criteria to those explanations that it applies to naturalistic ones. At one time, thunder and lightning was thought to be caused by the gods. Now we have a better explanation in terms of electric charges and dielectric breakdown. Supernatural explanations for floods, droughts, illness, the diversity of life, the motion of the planets, and so forth, have likewise been abandoned. The problem is not that supernatural explanations cannot be considered, it's that they just don't work. 

So why is it that even many scientists think that science must a priori exclude supernatural explanations? As supernatural explanations have been increasingly replaced by natural explanations, proponents of the supernatural have beaten a retreat, and now hide behind some insulating barriers. Boudry &co. point out that, when confronted with example of poor "design," Michael Behe has replied that the Designer's reasons and intentions are unfathomable. For Behe, good design is evidence of a designer but bad design is not counted as contradictory evidence. He is apparently not bothered by the blatant double standard he employs. (Boudry et. al. also mention that this type of immunization strategy is typical of pseudoscience: think of the psychic who, when given a chance to prove that he can bend spoons with his mind under controlled conditions, suddenly finds that the vibes are so bad that he can't perform.)

Rather than offering claims that are demonstrably wrong, then, the proponents of the supernatural have turned to offering explanations that are unfalsifiable. It is not that supernatural claims are intrinsically untestable. Jesus said, "You can say to this mountain, 'Go, throw yourself into the sea,' and it will be done." (Matthew 21:21) That's a testable claim - and it fails the test, every time. So, instead, people offer the sort of explanation that can't be proven wrong, because it is untestable. But these sorts of claims are intrinsically unscientific: if it can't be tested, it's not science. 

The failure of supernatural explanations, and the success of natural ones, has resulted in increasingly crummy versions of supernatural explanation. So much so that many scientists now have the impression that untestable explanations are the only possible form of supernatural explanation. But that's not true: it's just that the testable versions have been tried, and found wanting.

Foxtrot on XKCD

Bill Amend, creator of the Foxtrot comic, draws a guest comic that channels XKCD surprisingly well. Turns out Bill is a former physics geek. Who knew?

Isaac Newton as a college kid

I am currently working on not one but two new courses so I will be posting less frequently. However, when I have time and something interesting to write about I hope to continue the blog.

One of the new courses is going to be based around a history of physics, so I am reading Never at Rest: A Biography of Isaac Newton by Richard Westfall. Newton came from a wealthy family, but his relationship with his mother and stepfather seems to have been somewhat strained. When he went off to college (Trinity College at Cambridge), he seems to have had little financial support from home. As a result, he went as a "subsizar." Subsizars were at the very bottom of the social scale at Cambridge. They had to do chores and errands for the other students: cleaning their boots, emptying their bedpans, and such fun stuff.

Newton seems to have had few friends (not surprising for someone in his social position) and little interest in the gambling, drinking, and  prostitutes that many students spent their time on. He does mention going to the tavern on occasion, but only after he had gotten his B.A. He plunged himself into books instead.

The curriculum was crusty and antiquated when Newton arrived. In principle, one studied the classics, meaning that you studied Greek so that you could read Aristotle. In practice, everyone knew that graduating was a formality once you were in. Newton's notebooks from his college days show that he started reading the standard texts, but soon left off without bothering to finish them. Instead, he started off on an unsanctioned path of study of his own invention.  He read Galileo, Robert Boyle, and Thomas Hobbes. He devoured Descartes, and began writing comments on him and others in a notebook he labelled "Quaestiones quaedam Philosophcae," pointing out ways that Descartes's theories could be tested by simple observations.

He figured out a way out of his lowly status, too. He began lending money to other students, and recorded these loans meticulously in a notebook. He did not record any interest paid on these loans - but presumably received some, for soon he was hiring other students to do the menial tasks he was supposed to do for others.

Graduation was not a problem, but what to do after it was. There were "elections" to scholarships for further study, held only once every three or four years. Newton's chance came up in 1664. His curious program of study didn't bode well for the outcome, however. His tutor took him to the newly appointed Lucasian professor of mathematics, Isaac Barrow. Barrow quizzed him about Euclid - but Newton had skipped Euclid, and worked his way painstakingly through Descartes's mathematical writings instead. Barrow never thought to ask Newton about Descartes - presumably one who understood so little of Euclid would have no knowledge of the newer, higher math. And Newton was too shy to mention it himself.

Nevertheless, Newton was given the coveted scholarship. How this happened is a mystery. Perhaps Barrow saw something of Newton's genius, and pushed him through. Perhaps someone else came to Newton's rescue, playing his patron. Certainly he would never have obtained the scholarship without someone supporting him from within the college. And without that support, Newton would not have been able to continue his studies. He most likely would have had to return to his family estate and play the landed gentleman role, overseeing the crops and the cattle. To that unknown benefactor, the world owes a great debt.

Direct link because you can't see the whole picture here.

Freaks of Nature

I just finished reading Evolution, Me, and Other Freaks of Nature, an enjoyable Young Adult novel about a girl caught between her convictions and her church. On the recording I listened to, author Robin Brande interviewed biologist and author Kenneth R. Miller, on whom she modeled the main teacher character in the book, Ms. Shepherd. Ms. Shepherd, like Miller, is both a scientist and a person of faith.

The interview made me think again about something that seems to me a big problem for anyone who thinks they can reconcile modern science and Christianity; namely, that evolution is a process that necessarily involves a tremendous amount of suffering. I can understand that, logically speaking, there is no problem with saying that evolution is the means by which God chose to create life on earth, including human life. But evolution's creative engine is the violent death through starvation or predation of most of the individual organisms that have ever lived. How do you reconcile that with the loving Christian God? I don't recall ever finding an answer to that, in Miller's book or anywhere else.

So, recalling that I had a copy of Finding Darwin's God on my bookshelf, I pulled it out to see what I could find. A section entitled "No More Mr. Nice Guy," begins like this:

Of all the concerns expressed by Christians with respect to evolution, the strangest, the least logical, the most bizarre is the idea that evolution is too cruel to be compatible with their notion of a loving God.

OK, this sound very promising: Miller is going to proceed to explain why this complaint is illogical and bizarre, right? Well, let's see.

Miller says we need to keep two things in mind. First, "cruelty is relative." He points out that his lobster dinner is a cruel death from the point of view of the lobster, but just a good meal for him. Second, "we cannot call evolution cruel if all we are really doing is assigning to evolution the raw savagery of nature itself. The reality of life is that the world often lacks mercy, pity, and even common decency.... Evolution cannot be a cruel concept if all it does is reflect the realities of nature...."

Well, but why not? It seems to me that all Miller has done is to re-state the problem. Life is cruel and frequently involves violent, painful death. Why would a loving, kind, God choose this as her means of creation? Saying that this is just the "reality of nature" doesn't answer the complaint in the least.

From here, Miller goes on to point out that contemporary research into the evolutionary origins of altruism shows that what we often think of as the "good" behaviors can arise out of evolution as well. Fair enough, but it doesn't have anything to do with the original complaint.

OK, so is the objection illogical? Let's try to lay it out as a logical argument from the point of view of a Christian who accepts evolution.

1. God created life on earth.
2. Life on earth arose through evolution.
3. Therefore, God chose evolution as his means of creation.
4. Evolution involves the suffering and death of living creatures.
5. Therefore, God chose a means of creation that involves suffering of living creatures.

How can Miller resist this argument? (1) is a basic assumption in Christian thought, and I don't think Miller would try to deny this. (2) is well-established scientifically and clearly accepted by Miller. You could object to (3) by saying God didn't have any choice in her means of creation - but this would deny God's omnipotence. Miller also clearly recognizes that (4) is true. So I don't see any way Miller can resist the conclusion (5).


The only response I know of to this argument is along the lines of "Sometimes suffering is necessary so that a greater good can come about." Miller doesn't make any attempt at such an argument, but it is a common response to the problem of evil. But does it make any sense in this context? I don't think so: surely, if God is omnipotent, and if her goal was to produce intelligent, moral, beings, she could have just zapped all of us into existence - plants, animals, humans, and all - without going through all the pain of millions of years of evolution.

Ayn Rand Is Always Right!

Back by popular demand! (OK, Jeremy asked about it.)

How to annoy a philosopher and other wise advice from Saturday Morning Breakfast Cereal.

The Many Worlds Interpretation Is NOT Deterministic

It seems that quite a few philosophers have gotten an erroneous idea about the Many Worlds Interpretation (MWI) of quantum mechanics, namely that it is a deterministic interpretation. Even the Internet Encyclopedia of Philosophy makes this incorrect claim. So, I feel I ought to set the record straight.

The classic definition of determinism is that, given the way the world is at some time, plus the laws of nature, the future is completely fixed. Now, in one sense, this definition is clearly satisfied by the MWI. If, by "the way the world is at some time," we mean the quantum state of the universe at that time, and by "the future" we mean the quantum state of the universe at some later time, then the MWI is indeed deterministic. For the MWI takes the quantum state to be all that there is, and the unitary evolution of the quantum state to be the complete dynamics of the state. And that evolution is deterministic: there is one and only one state at a future time, and it is completely determined by the quantum state at the earlier time. (Here I am omitting the very serious difficulties of this approach, including the dubious nature of such an entity as "the quantum state of the universe" and the even more dubious assertion that that state evolves in a unitary fashion.)


But this sense of "determinism" is completely useless for normal philosophical discussion.

The problem is very easy to see in the famous example of Schroedinger's cat. Let's assume that some quantum process yields a 50-50 chance of outcomes A and B, and we rig up some equipment so that if outcome A happens then a vial of poison is smashed and the cat dies, but if outcome B happens, then the cat lives. And all of this takes place inside a perfectly impenetrable box, so that we have no way of determining the outcome until we open the box. Then, according to the rules of quantum mechanics, the cat will be in a superposition of alive and dead states until  the box is opened.

In the MWI, an experiment like this has a determinate outcome: that the quantum state evolves into two branches, one with a live cat and one with a dead cat. But in the real world we don't see such superposition states. We see a live cat or a dead one. The MWI solves this by invoking decoherence, yada, yada, yada, so that the two branches are effectively split into different worlds that never interfere thereafter.

But now you see the problem: the future, in the normal sense of the word, involves the cat being either alive or dead, not both. And the MWI does not determine which future we will see. Indeed, from the point of view of the MWI, there is not even any sense in asking which outcome actually occurred, because both actually occurred, in different "worlds."

So in the case of the cat, the future (in the normal everyday sense) is undetermined. But it's much worse than this: anything that occurs because of quantum effects has an indeterminate outcome. But in the MWI, everything that occurs at all occurs because of quantum effects. So (almost) everything is indeterminate.

(The sole exceptions would be those events that occur with 100% probability: outcomes that are represented by operators for which the quantum state of the universe is an eigenvector. But, given that the wave function splits every time a quantum event occurs, we can be sure that none of the events of ordinary interest will have the state of the universe as an eigenvector.)

The thing is, even though the MWI has restored determinism of a sort to the description of the universe, it completely fails to predict what we will see in our particular future. John Earman says that the MWI exhibits ontological determinism, but at the price of "radical epistemic indeterminism."

Clearly, though, it is the indeterministic aspect that is relevant for most philosophical concerns. For example, in discussions of free will the question is often asked, "Could I have done otherwise?" And the MWI gives the emphatic answer, "Yes!" Because not only could I have done otherwise, but in some other "world" I did do otherwise. Austin missed his putt, but in some other world where the quantum events in his brain fired the neurons in a different way he made the putt.

Maybe it is possible to continue to do philosophy while keeping in mind the ontological viewpoint of the MWI - though I have to say I doubt it. But it would at least be a very different philosophy than what we have now, and all of the classic discussions would have to be revisited in light of that ontology.

Beliefs Don't Matter (as much as you think)

We atheists spend a lot of time and energy addressing the beliefs of religious folks. But many people are religious, or at least go to a church or synagogue or mosque or something, not because of beliefs, but for reasons that we could call "social."

Jerry Coyne of Why Evolution Is True discusses an article by Philip Kitcher, a Columbia philosophy professor:

Kitcher distinguishes what he calls the “belief model”—the form of faith that is initially built on truth claims about God, Jesus, Mohamed and the like—from three other forms of what he calls the “orientation” model: the forms of faith that begin with a person identifying secular goals and beliefs that he shares with others, and then choosing a faith that properly frames these goals.

I think this is an important point that is often missed: as someone said, you can't rationally argue someone out a belief they weren't rationally argued into. (Or something like that.) And for most people, this must be the case. Most people follow the religion they were brought up in - it is a cultural issue, not a rational one.

It's an easy mistake to make, I think, because we are so used to thinking of religion in terms of beliefs. If you learn that someone is a two-seed-in-the-spirit predestinarian Baptist, you immediately ask, "What do they believe?"

But if we broaden our view and look beyond Western Christianity, we find there are many religions that are more interested in what you do than in what you believe. Strangely, in talking about non-Christian religions we often implicitly acknowledge the fact. We have no problem with the idea of "non-religious Jews," or people who are "culturally Jewish" without being "observant." When was the last time you heard of a "non-religious Christian"? Or heard someone say, "I'm culturally Christian, but I'm not observant"?

So, while New Atheist-type books and blogs may be very valuable in reaching a certain segment of the population, they may be missing an even larger segment. We need more secular versions of what the churches offer: communities with shared goals and values. Some existing groups - Quakers, Unitarian Universalists, and Ethical Societies - are based more on shared values than on shared beliefs, though of course the first two still involve some elements of religious belief. How do we build secular versions of these communities?

It's an interesting and important discussion, and I encourage you to read about Kitcher's article at the link above and at Russell Blackford's blog. (I linked the first post in a series: you can find the rest of the series in his sidebar.)

The Relativity of Wrong

In a previous post I argued that scientists choose their theories, not on the basis of which one is more likely true, but on the basis of which one gives a better approximation to reality.

Via a comment on Cosmic Variance, I came across an essay by Isaac Asimov that makes a similar point.

The young specialist in English Lit, having quoted me, went on to lecture me severely on the fact that in every century people have thought they understood the universe at last, and in every century they were proved to be wrong. It follows that the one thing we can say about our modern "knowledge" is that it is wrong. The young man then quoted with approval what Socrates had said on learning that the Delphic oracle had proclaimed him the wisest man in Greece. "If I am the wisest man," said Socrates, "it is because I alone know that I know nothing." the implication was that I was very foolish because I was under the impression I knew a great deal.

My answer to him was, "John, when people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together."

The basic trouble, you see, is that people think that "right" and "wrong" are absolute; that everything that isn't perfectly and completely right is totally and equally wrong.

However, I don't think that's so. It seems to me that right and wrong are fuzzy concepts, and I will devote this essay to an explanation of why I think so.

A No-Brainer?

This post is part of my series on physicalism.

When I started reading about physicalism I thought, "This is going to be a no-brainer - a piece of cake - a  clear shot at an open goal - a badly mixed metaphor." After reading these two books, I am impressed with the difficulty of the task. I think I understand a little better, too, how people like Trent can be so skeptical of the whole operation.

The issue with defining "physics", so that we can know what to reduce everything down to, seems almost a red herring. After all, if we could show that mental processes reduce down to events at the neural level, I don't think it would matter all that much (to philosophy) which definition of "physical" was taken to underlie the neural level. The biggest problem here is one that is glossed over briefly by Poland and sidestepped entirely by Melnyk: namely, the problematic nature of the ontology of quantum mechanics. If the wave function cannot be consistently interpreted as an actual, physical object (as I would argue), then it can't be the foundation for ontology for everything else. Poland waves such worries aside and says these things are for the physicists to worry about: whatever they come up with as the basic ontological entities are fine with him. But what if those basic entities can only be defined in term of large-scale, macroscopic quantities and measurements, as quantum mechanics seems to do? Then physicalism might justifiably be accused of circularity.

The more important point, it seems to me, is the issue of "realization." These two authors agree that supervenience is too weak, and identity theses are too strong. If realization gives a coherent account of how higher-level things are related to (reducible to) lower-level things, then something of real importance has been achieved. And this achievement is independent of the issue of what sort of physics is at the base of it all.

Finally, is realization physicalism (or something like it) is actually true? It is not so clear what, exactly would count as evidence in favor of, or against, physicalism. Melnyk spends two chapters considering the question and looking at the evidence, such as it is. He points out that some phenomena that might have turned out to be clear evidence against physicalism - psychokinesis, for example - have not panned out so well. On the other hand, more positively, every sort of mental activity seems to be associated with some sort of brain activity (e.g. as revealed in functional MRI investigations). He notes, too, that as recently as 1925 a prominent philosopher, C. D. Broad, could doubt that chemical phenomena were reducible to underlying physical laws, whereas now it is clear that the rules of quantum mechanics explain much of chemistry.

In short, physicalism has suffered no decisive defeat and has scored many major victories. This alone doesn't settle the matter, of course., and dualists and theists will continue to assail the physicalist position.

I still think that physicalism is clearly the most reasonable view - simply because of the complete lack of evidence for anything that is not physically realized. In this it is just like atheism: show me the evidence for your god, and perhaps I'll believe in him. (Or her.) (Or it.)

More About Physicalism

This post is part of my series on physicalism.

Some important points about Poland's and Melnyk's versions of physicalism:

The scope of physicalism. According to Poland (p.227),

The theses of physicalism apply to all natural phenomena and all claims to truth and knowledge concerning the natural order.

This leaves one wondering what, exactly, constitutes the "natural order." Poland lists

...physical, chemical, and biological phenomena, ... the psychological, the social, the moral, the aesthetic, and the commonsense world of our everyday experience.

However, he excepts purely abstract realms such as mathematics.

Melnyk is (again) more specific, saying that physicalism applies to everything that is either contingent or causal. The existence of a god who is not contingent (because he is a necessary being) but who causally affects, or is affected by, the world, would refute Melnyk's physicalism. (It seems that such a god would not refute Poland's version, as god is presumably outside of the natural order.) Mathematics, being composed of necessary (i.e. not contingent) truths that have no causal efficacy, is exempt here as well.


Realization physicalism entails supervenience. That is, the physical facts about the world determine all objective facts about the world.

But supervenience by itself is not enough to guarantee the kind of physicalism that we want. And supervenience doesn't entail realization physicalism. Thus, realization physicalism is a stronger claim than supervenience.


Physicalism is reductionistic. I was surprised to learn that "reductionism" is a bad word among philosophers. I thought that reduction was the whole point of science: to find explanations of things in terms of simpler, more fundamental things. Melnyk spends a whole chapter (cutely titled "Physicalism and R*d*ct**n*sm") discussing in what sense realization physicalism is, and in what sense it is not, reductionistic. He argues that it is reductionistic in the "core sense." The core sense, briefly, is that all higher-level facts have an explanation in terms of physical facts and necessary truths (such as logical and mathematical truths).

However, realization physicalism does not satisfy what Melnyk calls the "received sense" of reductionism, namely that each higher-level type is identical with some physical type. And Melnyk's version of physicalism is stated in terms of functional, not physical, types. In particular, a functional type can be one that satisfies a purely logical condition. (An example would be the computer program considered earlier.) While realization physicalism requires that all actual instances of such a higher-level type are realized physically, it does not identify the higher-level type with those instances, or the collection of all possible such instances, or anything like that.

Other Errors To Avoid: Poland writes (p.41)

[T]here is good reason to avoid such views at that everything is completely physical, physics is the one true theory, physics describes and explains everything, the only ... legitimate methods of inquiry are those of physics, and everything is best understood from the perspective of theoretical physics.

I have to agree with him here - except for the last one, which is self-evidently true.

Non-physical Things Exist!

This post is part of my series on physicalism.

Physicalism doesn't deny the existence of the non-physical. Indeed, the whole point of physicalism is to explain the non-physical in terms of the physical - and one doesn't try to explain things that don't exist.

I reject as false the view that every attribute is a physical attribute. (Poland, p.188)

Melnyk calls this "retentive realizationism." He reserves the option of "going non-retentive" if necessary, however. For example, he says, if it turns out that "life" cannot be explained as a functional property of physical systems, then the physicalist can deny that "life" exists, and replace it with some appropriate (physically realized) functional property that does exist. This is not as radical as it sounds. He points out that anyone objecting to this move would have to show that, in addition to such functional properties as being able to take in sustenance and transform it into parts of the body, and being able to reproduce, there is something called "life" that is real, while at the same time being above and beyond any such functional properties.

The difference is between explaining something and explaining it away. Take ghosts, for example. If you believe in ghosts, then you might explain them by saying, "Ghosts are the manifestation of spirits of the dead."  If you don't believe in them, you might explain them away: "Ghosts are psychological effects brought about by a deep emotional connection with someone who has died."

Physicalism is in the business of explaining the non-physical, not explaining it away. Consider, for example, a chemical compound that is made of (realized by) some combination of atoms, or an organ - say, a liver - that is composed of some collection of cells. To say that the compound, or the liver, is so composed is not to say that it doesn't exist! Rather, the physical realization allows us to explain why the compound has the chemical properties it does, why the liver functions as it does, on the basis of the underlying structure of atoms/cells and their, more fundamental, properties.

Computers and Minds

This post is part of my series on physicalism.

I like the computer program example so much I want to expand on it beyond what Melnyk says.

Take two computers, one a PC and one a Mac, that are both running some program (say, Windows 7). The two have different processors that must be programmed with different machine languages, so the actual physical events that occur in each computer will be quite different. Yet, if the programming and compiling has been done correctly, the two will be functionally equivalent. The two screens will look the same, and the same changes will occur when I click on the same icon on each.

Even if we were unaware of the details of the program the two computers were running, a careful investigation would reveal the existence of certain groups of physical processes that correspond to particular subroutines of the program in both computers. Thus, the physical-level description could be used to explain why the two computers were behaving in the same way. 

But the existence of a physical-level explanation doesn't invalidate an explanation at the level of the program itself. The same phenomena can be described in terms of IF-THEN statements and FOR loops. Realization physicalism says both types of explanation are valid.

This makes a terrific analogy for understanding the physical realization of mental phenomena like thoughts, emotions, or qualia. There is no way that the physical events occurring in my brain when I look at a red wall are the same as the events occurring in your brain when you look at the same wall. But I see no reason to doubt that there might be a functional equivalence of some sort between the events in the two brains, in a similar manner as between the two computers. It might even be possible, at some point in the future, to analyze the patterns of neural activity and identify groups of processes that correspond to particular aspects of the visual experience. These patterns could then be used to explain why the two people were having a similar experience.

Here, too, the existence of a physical-level explanation doesn't invalidate the explanation of mental phenomena at the level of mental events. ("The baby reached for the pacifier because it wanted something to suck on.") Physicalists don't deny the truth of mental causation any more than they deny that the billiard ball moved because it was struck by the cue ball. The existence of another description of both balls at the level of neutrons, protons, and electrons doesn't invalidate the causal efficacy of the cue ball. Rather, it explains it. And in the same way, the (postulated) physical realization of mental events explains (rather than denies) mental causation.

This is not to claim, of course, that science is at a point where it can prove the physical realization of mental phenomena. But the idea doesn't seem ridiculous on its face. The burden of proof, rather, lies with anyone who would claim that it is impossible for such mental phenomena to be physically realized.

A Sudden Realization...

This post is part of a series on physicalism.

The concept of realization is central to the physicalism program for both Poland and Melnyk. As it is more clearly laid out and (I think) more useful, I will follow Melnyk's version.

For Melnyk (p.26)

Every object is either an object of some physical kind or  a physically realized object of some functional object kind.

The same goes for properties and events: they are either physical or physically realized. The physical, as we have seen, is for Melnyk simply that which is describable in the proprietary language of fundamental physics. But what does it mean for something to be physically realized?

For Melnyk, higher-order types are functional types that are defined via an associated condition. A lower-order object (or property, or event) realizes a functional type if and only if it meets the associated condition.

This is a fairly abstract definition, and it would be really great to have an example here. Melnyk gives a few:

Examples of functional object kinds plausibly include can openers, digestive systems, and cells.... Examples of functional  properties plausibly include transparency, having currency, and being an analgesic.... Examples of functional event kinds plausibly include storms, births, and extinctions.(pp.21-22)

Unfortunately, he neglects to explain what the associated condition is for each of these examples. Perhaps the associated condition for being a can opener is "having the ability to open cans"?

At any rate, we can now say what it means for something to be physically realized:

A token x of functional type, F, is physically realized if and only if (i) x is realized by a token of some physical type, T, and (ii) T meets the associated condition for F solely as a logical consequence of the distribution in the world of physical tokens and the holding of physical laws. (p.23)

Here, again, it would be great to have an example or two, but unfortunately Melnyk doesn't provide any. So let me try to interpret this statement.

A can opener is an object of functional type in that it is capable of opening cans when wielded by a human (with some conditions of the human's strength, size, and mental ability presumably required). Note that "can" and "human" are not definable in purely physical terms, so they are (I think) non-physical in Melnyk's view.

The type "can opener" is physically realized if there is some configuration of atoms that meets the condition of being able to open cans, and does so purely by virtue of the physical properties of the atoms of which it is composed.

The can opener is a bad example, because probably no one doubts that can openers are physically realized. Later, Melnyk gives a really interesting example: a computer program.

A computer program is about as non-physical as something can be. It's an abstract set of processes relating some inputs to some outputs. It's really a mathematical function of a particular sort, though we don't usually talk about it that way. You can, of course, write it down, or type it into your computer so that it is stored in memory, but that doesn't make the program physical any more than writing down your thoughts makes them physical.

A computer program is a great example of a functional type. A particular computer can be said to be running the program if the the physical bits of the computer act according to a certain pattern: they are "related to one another in mathematically specifiable ways." (p.40) In Melnyk's language, those mathematical specifications are the associated condition, and any computer that meets that condition is realizing the computer program.

This, I think, provides an ideal example of what physicalism is all about. It doesn't deny the existence of abstract, non-physical things such as computer programs. But it claims that all actual instances of such things are physically realized.

It's OK To Admit You Don't Know

In the previous post I pointed out some difficulties with the idea of basing physicalism on current physical theory. Poland takes a different approach: he says physicalism should be based on the true physics, whatever that may be. Can we do any better with this approach?

It is important for Poland's program that there be determinate physical bases for physicalism.

By "determinate bases" I mean classes of entities that are well defined: for any entity, there is a fact of the matter as to whether it is included in the bases of the system or not.... Vacuous or indeterminate content, therefore, undermines the significance of physicalist doctrine.... (pp. 147-148)

Yet, Poland claims that it is not necessary that we know what the true physical bases are. It is enough to have a general definition of physics, so that we can recognize it when we see it. By basing physicalism on a general characterization of physics, rather than on any specific physical theory, Poland hopes to avoid the problem of the changing nature of physical theory.

Although our knowledge of the physical bases changes with physical theory, the actual bases themselves do not. And although current theory provides the best estimate of what is in the domain of physics and thus in the bases, it neither provides the content of physicalist theses nor determines their fate. (p. 166)

This seems to me to be a reasonable approach. (Melnyk clearly doesn't think so, but his objection seems to me to miss Poland's point.) In fact, Melnyk and Poland seem to be making a similar point: that it is the cart of physicalism, not the horse of physics pulling the cart, that is the focus of their philosophy. Realization physicalism is about how higher-level theories are related to lower-level theories, not about providing the specifics of the realization for every specific case.

I wonder if it would be better to drop the "physicalism" and just call it "realizationism." After all, if we were able to demonstrate that mental phenomena are realized at the level of neurophysiological processes (say), that would be a more than sufficient accomplishment for the program. It would hardly be necessary to further reduce the neurophysiological processes to the fundamental physical theory of the moment to declare success in a physically-based explanation of mental phenomena.

At any rate, I now need to tell you what "realization" means. I will turn to this task next time.

What Are The Error Bars On That?

I have been summarizing the physicalist views of two authors, Jeffrey Poland and Andrew Melnyk. In this post, I give my own opinions about Melnyk's view. Caveat lector!

Melnyk thinks that physicalism should take as its basis the current consensus physics of practicing physicists. At first I thought this a reasonable approach, but the more I thought about it the less I liked it. I see two very serious problems with it:

• - What if the best current theories of physics are not even logically consistent with each other?
• - What if the ontological basis of current physics is itself problematic?

On the first point, I think many physicists would agree that General Relativity (GR) and current particle physics theories (especially the Standard Model - SM) are logically inconsistent. This is a big problem for Melnyk, because he says the attitude that we should take toward physicalism is the "scientific realist (SR) attitude," that is, to "assign the hypothesis a higher probability than its relevant rivals." (p. 227) But if two theories are logically inconsistent, then we can't assign their joint probability as anything other than zero.

(Some might argue with my characterization of these theories as inconsistent. However, it is easy to see that, historically, there have been many times when our best physical theories were logically inconsistent: for instance, around 1900 Maxwell's electrodynamics was inconsistent with Newtonian mechanics. So physicalism must at least recognize the possibility that, at some given time, a fundamental inconsistency might exist in the physical theory basis.)

On the second point, I would say that we are in exactly this situation with respect to quantum mechanics. The ontological status of the quantum wave function (or state vector) is a matter of considerable dispute. Does it represent something physical, or does it represent our state of knowledge? The latter is my own view, but this seems to create a huge difficulty for physicalism: If all large-scale phenomena are based on (realizable as) quantum phenomena, and quantum phenomena are only understandable as probabilities of certain large-scale phenomena (output of sensors, counters, and other experimental apparatus), then physicalism is in very great danger of circularity.

I don't know what to do about the second problem - this seems like a very serious problem to me. But I have a suggestion about the first. I think Melnyk is simply wrong about the SR attitude being the view of practicing scientists. After all, how could we physicists simultaneously endorse GR and the SM while acknowledging their inconsistency? I think scientists' (or at least physicists') attitude is better described as the "good approximation (GA) attitude." That is, GR provides a good approximation to how the universe works at the largest scales, and the SM provides a good approximation at the smallest scales. Physicists - in spite of what they might themselves say - are not actually interested in whether a theory is true. They are interested in whether it works.

In fact, they have to be. Let me explain. I'll ignore GR for the moment and pretend that all we need for a fundamental theory of physics is a theory of particles and their interactions. Now, the Standard Model consists of some equations that contain various parameters that must be experimentally determined: the speed of light, Planck's constant, the electron's charge, the masses of the quarks, and so forth. Let's suppose that there is a true theory of the universe that is exactly the equations of the SM with some values of those parameters. Let's call that theory SM-true. Our current theory has the same equations, but with some "best fit" values of those same parameters. Call that theory SM-bf.

Now, the probability that SM-bf and SM-true are the same theory is precisely zero. There is zero chance that the specific values that we have deduced from experiment are identical to the true values. It is like trying to hit an infinitesimally small bull's-eye with an infinitely thin dart. (Mathematically, the true value is a set of measure zero in the space of possible parameters.) Certainly, the relevant rivals of our SM-bf would include other SM-like theories with other values of those parameters. But the probability of each of those rivals is zero, too! So the SR attitude is useless in deciding among these rivals.

If you go look up the values of those parameters, you will see them listed with experimental uncertainty after the value. These are what we sometimes call the "error bars." What those uncertainties mean is this: we have no confidence that the parameter takes on the exact value listed, but we have high confidence that the true value lies within the range specified by the value and the experimental uncertainty.

I think endorsing a theory by taking the GA attitude should mean that we believe the universe will behave approximately as described by the theory, where "approximately" means "within the range of expected outcomes as determined by the range of experimental uncertainty in the parameters of the theory, as long as the values of relevant external parameters are within a specified range." Here "external parameters" refer to physical values that are characteristic of the particular situation in question, rather than parameters appearing in the theory. External parameters might include relative velocity, center-of-mass energy, and so forth.

By taking the GA attitude, we can endorse a theory even if we are sure (by reason of logical inconsistency, for example) that it is not a true theory. Thus, we can say that GR is a good approximation at large values of some external length parameter, and SM is a good approximation at small values of that parameter, while not claiming that either one is (or is an approximation to) a true theory.

Melnyk mentions the possibility of treating physicalism as approximately true (p. 225), but dismisses it on the grounds that notions of approximation to the truth are "notoriously hard to explicate satisfactorily." But, given the difficulties of Melyk's own account, and given the fact that physicists have to deal with approximations to the truth all the time, and have developed tools for doing so quantitatively, I think that this must be a more promising avenue than his own.

Physics is Fundamental!

This post is part of a series on naturalism.

In realization physicalism, as described by Poland and Melnyk, everything that exists is either physical, or is realized by a physical property or system. As a physicist, I at first found this starting point very attractive. Of course, physics is at the base of everything! And of course, we should take it as our starting point for our philosophy! (I'm starting to think there's a serious problem with this idea, but I'll save that for a later post.)

But what does it mean for something to be physical? Here Poland and Melnyk part company in an intriguing way.

We start with an apparently fatal dilemma for physicalism. Suppose that by "physics," we mean "physics as currently understood by practicing physicists." Then we have a problem: current physics, as any physicist will admit, is incomplete at best, and inconsistent at worst. Sure, it does a terrific job of approximating what the universe does, but there's very small likelihood that it is a true description of the world. Historically speaking, the best physical theory has turned out, over and over again, to be incorrect. New theories replace old theories all the time: what justification do we have to think that our current best explanation is any different?

But if physicalism is based on a theory of physics that is not true, then physicalism cannot be true, either.

Suppose, though, that we don't base physicalism on the current theories of physics. Then what do we base it on? Some future physics, that (we hope) will be an exactly true description of the world? Even if we had any expectation that we might some day reach that lofty goal, we do not know today the content of that future theory. So physicalism has no determined content: everything reduces to a physics that we know nothing about.

This is known as Hempel's Dilemma, and Poland and Melnyk grasp different horns.

Poland asks why we should believe that physicalism only has determinate content if there is a specific physical theory on which it is based. He points to determinism: philosophers have no trouble accepting that determinism is a meaningful concept, even if it does not refer to a specific deterministic physical theory. Poland argues that, similarly, physics is a meaningful term, even if we don't have a specific physical theory in mind.

If there is a true physical theory that correctly describes the reality that current physical theories purport to describe, then, regardless of whether we ever hit upon such a theory, it and the reality it describes exist and constitute the physical bases required by physicalist theses. (p. 162)

Physics, according to Poland, is

the branch of science concerned with identifying a basic class of objects and attributes and a class of principles that are sufficient for an account of space-time and of the composition, dynamics, and interactions of all occupants. (p. 124)

Poland thinks the dilemma is a false one. He thinks the cart of physicalism can be hitched to a horse called "physics," so defined, rather than to any specific physical theory.

Melnyk firmly declares that physicalism should be defined in terms of current physics. He also agrees that current physics has very little chance of being true. Thus, physicalism so defined has very little chance of being true. He then makes a rather strange move: he says that we can nevertheless endorse physicalism. A physicalist can "comfortably live with the result that physicalism has a very low probability."

To be a physicalist is to take the same attitude - whatever that attitude is - toward the hypothesis of physicalism that those who have broadly realist and antirelativist intuitions take toward what they regard as the best of current scientific hypotheses. (p.225)

Thus, "physicalism is viewed as no more and no less than a scientific hypothesis," (p. 226) and so should be held to the same standard as scientific theories.  These theories do not have a high probability of being true - they are constantly being refined and replaced, after all - but they are "the best we have so far." So, too, for physicalism.

But what happens when physical theory changes? Then, Melnyk says, physicalism as currently defined will have to change, too. The new physicalism will not strictly speaking be the same as Melnyk's physicalism (which is defined in terms of today's physics), but it will be a closely related view that retains the same structure as Melnyk's physicalism. Melnyk allows us to change horses without changing the cart of  physicalism.

I will leave you to ponder these two approaches: next time I will give my own take on them.

Hauser’s Mistakes

Thanks to Matt of Atheism: Proving The Negative, I have learned that Harvard's Marc Hauser, whose book I blogged about recently, is being investigated for possible fraud involving his research. Since I spoke highly of his book, I felt I should pass on the information.

A Gripe

We interrupt your irregularly scheduled discussion of naturalism to complain a bit.

Why can't philosophers learn how to use examples? When I'm teaching my physics classes, I can hardly say five sentences without feeling the need to throw in an example to illustrate whatever it is I'm talking about. There's nothing like a good, clear example to show what the abstract terms mean and how they are used in practice. But philosophers are capable of going on and on for hundreds of pages of the most abstract stuff without a single example.

I noticed this while reading about free will. Practically the only example I ran across was Austin's putt. (Certainly the most over-analysed event in sporting history. That's another thing about philosophers: once they get hold of an example they worry it to death.)

In the two books on physicalism that I'm reading it's just as bad. Melnyk is the better of the two: he occasionally describes a useful example. I'll report on one or two of these in upcoming posts.

But Poland goes on about "function" and "causality" and "instantiation" and "tokens" and so forth, never pausing to give an illustration of what these terms mean in real life. And when he does give an "example," it's so abstract as to be nearly useless. For instance, in describing how the same sort of explanation is used for natural regularities as for exceptions to those regularities, Poland gives the following "example". (And no, I am not making this up. It's on p. 220.)

For example, if an exception to a causal regularity is a case in which the antecedent, but not the consequent, attribute is instantiated, some other attribute being instantiated instead, then such an exception is explained via an account which clarifies the relations between the attribute(s) realizing the antecedent non-physical attribute and the attribute(s) realizing the non-physical attribute that replaced the expected consequent non-physical attribute and which explains how those relations between the physically-based attributes realize the relation between the two actually occurring non-physical attributes.

Thank you so much, Professor Poland.

We now return to your irregularly scheduled discussion.

Naturalism, Materialism, Physicalism, Oh My!

This post is part of a series on naturalism. The first post is here.

I noted in that post Trent Dougherty's complaint that he couldn't find a decent defense of naturalism anywhere.

Has anyone given a decent academic case for naturalism? The closest I can recall is Melnyk's in his Material Manifesto. Maybe David Papineau's closure argument could be generalized. I think naturalists just assume it's all going to work out. It just seems utterly hopeless to me.

Despite Trent's complaints, I had little trouble finding serious philosophical defenses of naturalism. I am working my way through two of them: Physicalism, by Jeffrey Poland, and A Physicalist Manifesto, by Andrew Melnyk. Trent seems to have read the latter (though he got the title wrong), but gives no clue about what he found lacking in its presentation.

I am going to try to summarize the approaches taken by Poland and Melnyk. But first, why "physicalism" rather than "naturalism"?

According to the Stanford Encyclopedia of Philosophy, naturalism "has no very precise meaning in contemporary philosophy." It suggest a commitment to natural, as opposed to supernatural, entities and explanations. But, the SEP notes, "the great majority of contemporary philosophers would happily accept naturalism as just characterized," without necessarily accepting such ideas as being able to reduce mental phenomena to physical phenomena.

Materialism and physicalism are sometimes used synonymously. Materialism is sometimes taken to imply that only matter truly exists. Since Einstein discovered that E = mc^2 over 100 years ago, it is hard to believe that anyone would make this claim today. In contemporary understanding, matter and energy are interchangeable; they are, in fact, two aspects of the same thing. Thus, the materialist should at least expand the physical basis to include energy (or perhaps the energy-momentum tensor). Too, the term "materialism" has a variety of other uses, including Marxist and eliminative, which is perhaps why those writing about materialism in the current sense prefer the term "physicalism" (even though my spell checker doesn't think it's a word).

Physicalism, very roughly, is the idea that everything that exists is in some sense dependent on a physical substrate. But how to make this more precise? In what sense should higher-order phenomena (anything from a chair to the concept of justice in the mind of Antonin Scalia) depend on the purely physical facts about the world? Philosophers have proposed many different types of dependence.

• Identity: Everything that exists can be identified with some subset of the physical world.
• Definition: Everything that exists can be defined in the language of physics.
• Derivation: The laws of the higher-order sciences can be derived from the laws of physics.
• Supervenience: Any possible world that is physically indiscernible from the actual world is, in fact, completely indiscernible from the actual world.

While each of these captures some aspect of the physicalist thesis, Poland and Melnyk agree that none of them is completely satisfactory. Some are too strong: it seems highly unlikely that any purely physical system can be identical to the concept of justice in the mind of Antonin Scalia. Others are too weak: the indiscernibility requirement of supervenience can't guarantee that non-physical facts can be explained in terms of physical facts.

A better formulation, according to both authors, is given by realization physicalism: everything that exists is either physical, or is realized by a physical property or system.

That means we need to answer two questions. What does it mean for something to be physical? And what does it mean to be realized by something physical?

Next time: Physics is Fundamental!

Trent Doesn't Get Naturalism

Trent Dougherty of Prosblogion writes:

I just can't take naturalism seriously. That is, I can't take seriously any view that entails either the proposition that some contingent fact occurred for no reason or that in essentials, the universe (or world or nature or whatever you want to call it) couldn't have been relevantly different from the way it in fact is. And if I had to accept some set of contingent facts as brute, I'd be strictly guided by the number of types and tokens and parameters postulated by a theory. I also find implausible impersonal accounts of a necessary ground in some "natural" force or fact.

...the fact is I try extremely hard to take seriously all positions, especially rivals to my own views.... I read every academic book I can find defending atheism.... But when it comes to "Scientific Naturalism" in its many and varied forms, I draw a total blank. The Dennet/Dawkins/Hitchens/Harris stuff is a total loss. But there's not much better.

Trent's post really gave me a jolt. I've been an atheist for many years, primarily on the basis that there is simply no good evidence for a god of any sort, let alone the sort of god that Christians or other religious people propose. But if it's reasonable for atheists to ask theists to defend their worldview, then certainly turnabout is fair play: it's reasonable for theists to ask atheists to defend their worldview, too. But, surely, the picture can't be as grim for naturalism as Trent claims?

So I decided to look into it, both for my own benefit, to develop a more coherent personal worldview, and so that I can defend that worldview if I ever run into someone like Trent: intelligent, educated, highly sophisticated philosophically, and theist.

My intuitive understanding of naturalism was in terms of reductionism: all phenomena are, at root, physical phenomena. But there are phenomena we all experience that are not obviously reducible to physical phenomena: mental phenomena like ideas and perceptions. One need not be an atheist to think that mental phenomena are of a different order than physical phenomena. For instance, a Cartesian dualist might hold that there are embodied spirits, while denying the possibility of disembodied spirits.

On a naturalist account, mental phenomena reduce to brain phenomena, brain phenomena reduce to interactions among neurons, interactions among neurons reduce to biochemical processes, and biochemical processes reduce to physical processes among protons, neutrons, and electrons. But how is this reduction to be achieved? And what, if any, reason is there to accept this view as opposed to any other view?

Next time: Naturalism, Materialism, Physicalism, Oh My!

Moral Anti-Realism

This post is part of a series on theories of ethics: first post, second post.

Moral anti-realists deny that moral values are mind-independent. We have already encountered one version of anti-realism: non-cognitivism, which claims that moral statements are not the sort of things that can be true or false, rather, they are ejaculations roughly equivalent to "Boo!" or "Yuck!"

The flip side of this is moral error theory, associated with J. L. Mackie. Error theory is a cognitivist theory - moral statement are capable of being true or false - but the error theorist claims that, in fact, no such statements are true, because they all reference things (moral values) that don't actually exist.

The moral error theorist stands to morality as the atheist stands to religion. (SEP)

Finally, there is ethical subjectivism, that holds that moral facts exist but are mind-dependent in some way: morality is about mental attitudes rather than about objective moral entities that exist "out there."  One version of subjectivism is moral relativism: moral truths are relative to the individual, or to the group to which the individual belongs. However, it is possible to be subjectivist without being relativist, and vice versa.

This completes the overview of the main approaches to ethics. I can't resist adding some comments of my own here.

There seems to be - in the sources I have looked at, at least - considerable tension between prescriptive approaches to ethics (how should one go about making moral decisions) and descriptive ones (how do people actually go about making moral decisions). Some ethical theories (utilitarianism, for example) are clearly intended prescriptively, while others (error theory) just as clearly are not. All these are lumped together under the label "metaethics." It seems to me that these ought to be two completely different disciplines.

On the descriptive side, I have been reading Moral Minds, by Harvard's Marc Hauser. His approach (and that of the researchers he cites) promises to be a game-changer in descriptive ethics. He describes numerous experiments in which people are presented with moral questions (e.g. the famous trolley problems) and must decide what actions are permissible, obligatory, or forbidden. He relates cases of people with various mental impairments and discusses how these illuminate models of moral decision-making. He argues for a Chomskian approach. We are born with some innate ability to learn language, but the specifics of the language we learn are shaped by the linguistic environment in which we grow up. So with morality: we are born with some innate moral capacities, but the specific morality we end up with is shaped by the cultural environment. Whether or not his view turns out to be fruitful, it seems certain that we will learn more about how moral decisions are actually made by way of experiments of this sort than by the armchair speculations of philosophers.

But where does this leave us as far as the prescriptive side of the issue? Does learning about how people make moral judgments help us decide how people ought to make moral judgments? It seems we have here a meta-version of Hume's is-ought problem: no amount of research on how moral judgments are made will tell us how they ought to be made.

Naturalism self-destructs?

A claim frequently expounded by theists is that naturalism is self-defeating: the claims of naturalism, if true, would prevent anyone from ever knowing that they were true. Anthony Flew devotes a chapter of Atheistic Humanism to this claim.

He quotes J. B. S. Haldane:

I am not myself a materialist because if materialism is true, it seems to me that we cannot know that it is true. If my opinions are the result of chemical processes going on in my brain, they are determined by the laws of chemistry, not those of logic.

Flew says Haldane later repudiated this line of reasoning. Nonetheless, let's try to lay it out logically.

Naturalism is self-defeating, version 1 (NSD1):

1. My opinions are either the result of chemical processes or logical processes.
2. If naturalism is true, then my opinions are the result of chemical processes.
3. Therefore, if naturalism is true, my opinions are not the result of logical processes.

The problem here (Flew points out) is with (1.). This is a false dichotomy: there is no reason to think that the result of chemical processes cannot also be the result of logical processes. It's like saying, "Why trust the output of that computer when you multiply two numbers with it? It's just the result of electronic processes, so it can't be the result of mathematical rules!" The mistake here is that the electronic circuits of the computer have been set up precisely so that they implement mathematical rules. There is no conflict between the physical description (electrons) and the logical description (multiplication).

Flew goes on to say that Popper gave a different version of Haldane's argument.

...if "scientific" determinism is true... we believe it,not because we freely judge the arguments or reasons in its favour to be sound, but because we happen to be so determined (so brainwashed) as to believe it....

Flew elaborates that the question has now become

...whether we could by any means have believed other than we did. Unless we could  we cannot take credit for having, as rational beings, judged that these beliefs are true.

Let's call this

Naturalism is self-defeating, version 2 (NSD2):

1. If naturalism is true, the world is deterministic.
2. If the world is deterministic, then our beliefs are determined by things outside our control.
3. If our beliefs are determined by things outside our control, then we could not have believed otherwise than we did.
4. If we could not have believed otherwise than we did, then our beliefs are not the result of a rational judgment.
5. If  our beliefs - specifically, our belief in naturalism - are not the result of a rational judgment, then there is no rational reason to go on believing in naturalism.

The reader will notice that this is, essentially, a version of the Consequence Argument. The issue of naturalism has become an issue of free will.

Flew appears to accept this version of the argument:

...naturalism is in this way refuted in as much as such a naturalist can be taken, as surely he must be, to be claiming nothing more nor less than to know that his scientifically grounded naturalism is nothing more nor less than true.

I find this sentence confusing and cluttered, so let's redact the unneccessary verbiage:

...naturalism is in this way refuted in as much as such a naturalist can be taken to be claiming to know that his scientifically grounded naturalism is true.

In his Epilogue to the chapter, however, Flew clarifies that this is only the case if the words "explain naturalistically" are taken to mean an explaining away of the phenomena. For Flew, on the contrary,

...explanations of the physical aspects of the behavior of these organisms in terms of physical causes are not necessarily irreconcilable rivals to explanations of other aspects of that behavior in irreducibly different terms.

It seems to me, though, that Flew concedes too much. NSD2 fails on several counts. First of all, Premise (1.) is simply false: our best accounts of the fundamental workings of the physical universe are not deterministic. Secondly, even if Premise (1.) should somehow turn out to be true, the rest of the argument suffers from the same issues as the Consequence Argument - specifically, the fatalism fallacy.

So, I don't see any reason to accept either version of NSD.