Pachydermist: I believe there are purple space elephants living on the planet Pluto.*
Apachydermist: Um, OK, what evidence do you have for that belief?
Pachydermist: I have the ability to sense them directly. Whenever I feel a tingling in my left little toe, I know that these elephants exist. I call this my sensus elephantiasis, because everything sounds more impressive in Latin.
Apachydermist: And you feel this tingling...?
Pachydermist: All the time.
Apachydermist: Riiight....
Pachydermist: Well, can you prove that there aren't any purple Plutonian pachyderms?
Apachydermist: I know I'm going to regret this, but here goes. Let's start off with the easy stuff. There can't be any elephants living on Pluto, because Pluto has no air and elephants need air to breathe.
Pachydermist: Ah, but you don't understand. These are space elephants, they don't need air to breathe.
Apachydermist: Well, they wouldn't have anything to eat or drink on Pluto.
Pachydermist: Space elephants! Space elephants! They don't need any stinkin' food or water!
Apachydermist: OK, but look: if these things don't eat or drink or breathe air, and they're not related to Earth elephants by descent or ancestry (how would they have gotten to Pluto from Earth, or vice versa?) then they can't in any meaningful sense be elephants, can they? I mean, if these things are so utterly different from anything we know as an elephant, then there's no sense in calling them elephants.
Pachydermist: Ah, but these are the true, essential elephants. Our Earth elephants are but a pale shadow of their perfect pachydermic nature.
Apachydermist: And you learned all of this from a tingling in your toe?
Pachydermist: Yes, and through pure logic.
Apachydermist: Uh, right, logic. I knew I was going to regret this. Well, just to prove you wrong, I'm going to build a spaceship and travel to Pluto and search for these elephants.
Pachydermist: OK, sure, but it won't do any good.
Apachydermist: Huh? Why not?
Pachydermist: You see, these space elephants are invisible.
Apachydermist: Invisible? You said they were purple!
Pachydermist: Yes, but they are the essence of true purple. The color we know as purple on Earth....
Apachydermist: ... is but a pale shadow, yeah OK I get it. But I'll make a huge cordon across the entire planet and corral the elephants...
Pachydermist: Sorry, they're not only invisible, they're intangible, too.
Apachydermist: Intangible, too? What are they made out of?
Pachydermist: An immaterial substance.
Apachydermist: Immaterial substance? It seems to me that translates as "immaterial material", or "substance which has no substance." I think I've finally found something we can agree on. Your pachyderms are oxymoronic!
Pachydermist: Actually, they're very smart. They have a level of intelligence compared to which human intelligence is just ....
Apachydermist: (Exits stage left, shaking his head sadly.)
Very silly, I know. But these are the same arguments theists use against atheists, as I will demonstrate over the next few posts. I don't know when I'll get to those posts, so in the meantime, you can try to guess whose arguments I'm thinking of. Have at it!
* Pluto is now considered a dwarf planet, but a dwarf planet is a planet, too, right? So no complaints about "Pluto is no longer a planet! Aaaugh!"
Thursday, October 18, 2012
Sunday, September 23, 2012
Act and Potency in Physics
A while back, BeingItself commented on this post by quoting Ed Feser:
BI then asked,
This is a great question, and I thank Mr. Mosis for bumping it back to my attention. I really have no idea what the answer is. Although I've read a fair smattering of philosophy of science and philosophy of physics, I can't recall ever coming across a discussion of the metaphysical assumptions underlying physical theories - not even in discussions of the foundations of quantum mechanics, where some sort of metaphysical groundwork would really be useful. As Feser points out in the linked article,
(I suspect one reason philosophers avoid these issues is the fear of having the rug pulled out from under them by physicists. Anything any philosopher wrote on time, for instance, probably sounded remarkably silly after Einstein revolutionized our concepts of space and time.)
Let's start with classical mechanics. (Quantum mechanics is a whole different ball of wax, and its interpretation remains very controversial.) The basic entities we work with are:
We then proceed to write equations for how the particles and fields change in time. (Newton's laws for motion of particles, and Maxwell's equations for the changes of fields, for example.) Here the possibility of change is implicit in the fact of a time coordinate: there is no reason to assume that what obtains at one time also obtains at some other time. So, my first reaction to BI's question was to think that of course there's nothing like act and potency in physics. We just talk about change as a fundamental fact about the universe.
When I read Feser and his Aquinas quotes on actuality and potentiality, it seemed as though they were saying that the actual is real, and the potential was sort of real, too, as if it were sitting around somewhere waiting to be pushed into actuality. This seemed like a quaint, medieval idea that had no relevance to modern physics. But the more I thought about it, the more I began to realize that we actually have an approach in physics that very closely resembles this. That is the idea of a state space.
The state space is the collection of all possible states of the system. For a point particle, the state consists of its position and its velocity, or state of motion. For a single particle moving in one dimension, the state space consists of the two-dimensional plane (x,v). The particle's motion is then envisioned as a path in this plane. So, we do indeed think of the possible states of the particle as sort of existing "out there", and the (actual) particle as moving from one of these states to another.
So is Feser right - does modern physics presuppose the notions of actuality and possibility? I'm not convinced. For one thing, the whole notion of state space wasn't developed until the 19th century (by Hamilton, I think). And for another, the state space picture doesn't remove the need for a time coordinate. As I said before, the existence of time already allows for the possibility of change. And we can't even talk about the state space without the notion of velocity, which itself requires time. So it seems to me that the concepts of time and change are metaphysically prior to those of potentiality and state space.
The Aristotelian theory of act and potency is the classic example of such a piece of middle ground knowledge. It is grounded in the basic empirical datum, the fact of change. But it is not a description of this or that particular change or this or that particular kind of change but rather of all change as such. Hence while empirically grounded it is not subject to falsification by theorizing in physics, chemistry, etc., because the phenomena dealt with in all such theorizing, since they all involve change, implicitly presuppose the theory of act and potency.
BI then asked,
Do you think that is correct? Do physicists presuppose this metaphysics?
This is a great question, and I thank Mr. Mosis for bumping it back to my attention. I really have no idea what the answer is. Although I've read a fair smattering of philosophy of science and philosophy of physics, I can't recall ever coming across a discussion of the metaphysical assumptions underlying physical theories - not even in discussions of the foundations of quantum mechanics, where some sort of metaphysical groundwork would really be useful. As Feser points out in the linked article,
[F]or most of its history the philosophy of science was essentially concerned with questions about the methodology of science, the logical structure of scientific theories, the meaning of scientific assertions, and the like...Feser says there has recently been a return to metaphysical issues, and links to some relevant books. Not having read these, though, I'm going to plunge in and try to give you an idea of how physicists go about their business.
(I suspect one reason philosophers avoid these issues is the fear of having the rug pulled out from under them by physicists. Anything any philosopher wrote on time, for instance, probably sounded remarkably silly after Einstein revolutionized our concepts of space and time.)
Let's start with classical mechanics. (Quantum mechanics is a whole different ball of wax, and its interpretation remains very controversial.) The basic entities we work with are:
- Space - the three-dimensional continuum that is the stage on which everything takes place.
- Time - is what keeps everything from happening all at once.
- Point particles - the actors on the stage. They are idealized objects that have a location in space at a given time.
- Fields - extended entities that exist at every point in space. They are produced by (certain types of) particles and they exert influence on (certain types of) particles.
We then proceed to write equations for how the particles and fields change in time. (Newton's laws for motion of particles, and Maxwell's equations for the changes of fields, for example.) Here the possibility of change is implicit in the fact of a time coordinate: there is no reason to assume that what obtains at one time also obtains at some other time. So, my first reaction to BI's question was to think that of course there's nothing like act and potency in physics. We just talk about change as a fundamental fact about the universe.
When I read Feser and his Aquinas quotes on actuality and potentiality, it seemed as though they were saying that the actual is real, and the potential was sort of real, too, as if it were sitting around somewhere waiting to be pushed into actuality. This seemed like a quaint, medieval idea that had no relevance to modern physics. But the more I thought about it, the more I began to realize that we actually have an approach in physics that very closely resembles this. That is the idea of a state space.
The state space is the collection of all possible states of the system. For a point particle, the state consists of its position and its velocity, or state of motion. For a single particle moving in one dimension, the state space consists of the two-dimensional plane (x,v). The particle's motion is then envisioned as a path in this plane. So, we do indeed think of the possible states of the particle as sort of existing "out there", and the (actual) particle as moving from one of these states to another.
So is Feser right - does modern physics presuppose the notions of actuality and possibility? I'm not convinced. For one thing, the whole notion of state space wasn't developed until the 19th century (by Hamilton, I think). And for another, the state space picture doesn't remove the need for a time coordinate. As I said before, the existence of time already allows for the possibility of change. And we can't even talk about the state space without the notion of velocity, which itself requires time. So it seems to me that the concepts of time and change are metaphysically prior to those of potentiality and state space.
Thursday, August 30, 2012
Ryan tl;dr
"Rich people need more money, so stop whining and suck it up, you poor people."
"Also, I hate big government-run medical programs. Also, I'll defend Medicare to the death."
The Republicans have become completely incoherent.
"Also, I hate big government-run medical programs. Also, I'll defend Medicare to the death."
The Republicans have become completely incoherent.
Thursday, August 2, 2012
Marriage and the word "bigot"
As an African American a non-white American, Hemant Mehta knows something about bigotry. He puts it better than I can:
Read the whole thing here.
You can’t say I love my black friends, but I don’t think they should be allowed to marry white people… without simultaneously being a racist.
Read the whole thing here.
Wednesday, July 4, 2012
Happy Higgs Day!
It's now official: the experiments at LHC have discovered the Higgs particle. Depending on how you slice and dice the numbers, they just meet the "5 sigma" criterion to claim discovery. Combined, they will certainly exceed that, but the official combination won't be available for a while. In the meantime, here's the unofficial combination.
The new particle has a mass of about 125 GeV (about 125 times heavier than the proton). You can read a brief description of the significance of this discovery here, but if you want the full story, read the book.
The new particle has a mass of about 125 GeV (about 125 times heavier than the proton). You can read a brief description of the significance of this discovery here, but if you want the full story, read the book.
Thursday, June 14, 2012
Are They Really The Same?
Are opponents of same-sex marriage really like opponents of interracial marriage of 50 years ago? Let's take a look at some of the most common objections to same-sex marriage.
Same-sex marriage is unnatural
Same-sex marriage is contrary to God and unBiblical
The trial judge who convicted the Lovings of illegal interracial marriage wrote
Same-sex marriage is against the traditional definition of marriage
Same-sex marriage is a slippery slope
R. D. McIlwaine, arguing against interracial marriage in the Loving case, made a slippery-slope argument, too:
So, yes - really the same arguments all over again. Haven't we learned anything from our history?
Same-sex marriage is unnatural
Here, for example, is the declaration that the Supreme Court of Virginia used to invalidate a marriage between a black man and a white woman in 1878:
The purity of public morals," the court declared, "the moral and physical development of both races….require that they should be kept distinct and separate… that connections and alliances so unnatural that God and nature seem to forbid them, should be prohibited by positive law, and be subject to no evasion.
As the New York Times (Feb. 23, 1911, p. 23) phrased it: The “white and black races should live apart. Their hybridization forms a degenerate type; anthropologists declare that some of the most cruel and treacherous specimens of humanity are to be found among “mottled” negroes.”A Georgia court wrote that such unions are “not only unnatural, but … always productive of deplorable results,” such as increased effeminate behavior in the population. “They are productive of evil, and evil only, without any corresponding good … (in accordance with) the God of nature.”
Same-sex marriage is contrary to God and unBiblical
The trial judge who convicted the Lovings of illegal interracial marriage wrote
Almighty God created the races white, black, yellow, malay and red, and he placed them on separate continents. And but for the interference with his arrangement there would be no cause for such marriages. The fact that he separated the races shows that he did not intend for the races to mix.This attitude was wide-spread among Christians. As recently as 1980 R. J. Rushdoony reiterated the Biblical argument against interracial marriage:
The burden of the law is thus against inter-religious, inter-racial, and inter-cultural marriages, in that they normally go against the very community which marriage is designed to establish.And even today, 16% of evangelicals continue to oppose interracial marriage.
Same-sex marriage is against the traditional definition of marriage
Allowing interracial marriages “necessarily involves the degradation” of conventional marriage, an institution that “deserves admiration rather than execration.”
(Source: A U.S. representative from Georgia quoted in Eric Zorn, Chicago Tribune, May 19, 1996)
Same-sex marriage is a slippery slope
R. D. McIlwaine, arguing against interracial marriage in the Loving case, made a slippery-slope argument, too:
It is clear from the most recent available evidence on the psycho-sociological aspect of this question that intermarried families are subjected to much greater pressures and problems then those of the intermarried and that the state's prohibition of interracial marriage for this reason stands on the same footing as the prohibition of polygamous marriage, or incestuous marriage or the prescription of minimum ages at which people may marry and the prevention of the marriage of people who are mentally incompetent.Think of the children!
It is contended that interracial marriage has adverse effects not only uponA host of other arguments
the parties thereto but upon their progeny . . . and that the progeny of a
marriage between a Negro and a Caucasian suffer not only the stigma of such
inferiority but the fear of rejection by members of both races.
(Source: Perez v. Lippold, 198 P.2d at 26 and n.5 (summarizing the State's
argument in favor of ban on interracial marriage))
So, yes - really the same arguments all over again. Haven't we learned anything from our history?
Monday, June 11, 2012
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