Tuesday, March 12, 2013

Knowing physics

Stephen Hawking knows physics. But what does that mean?

Is it a case objectual knowledge akin to Churchill knowing Chamberlain or my knowing my left knee? It seems not. For Hawking could know physics without physics as such being an object of his knowledge. For there are two senses of the word "physics".

The first referent of "physics" is a particular discipline. But a discipline is an object of knowledge for a meta-discipline. Thus, physics is an object of knowledge for the sociology or philosophy of physics and while a physicist, of course, can double as a sociologist or philosopher of physics, she need not. We could imagine a superb physicist but rotten philosopher who was simply oblivious to the idea of physics as a discipline, much as in the case of the Frenchman who talked prose all his life without knowing it.

The other sense of the word "physics" is the sense in which one talks of the "physics of the world", i.e., the true physics. But that Hawking knows physics could be true even if his physical theories turned out to be false, so when we say that Hawking knows physics, we don't mean that he knows the physics of the world. Copernicus knew astronomy, though he was fundamentally wrong about the "astronomy of the world"--the planets don't move in circles and there is nothing non-relatively at rest.

Perhaps "physics" is a mass noun here for the propositions of physics. So, when we say Hawking knows physics, we mean he knows enough of physics, i.e., enough of the propositions of physics. But again that can't be right. For it could be that the propositions of physics that Hawking accepts are false and yet Hawking knows physics.

So it seems that when we say that Hawking knows physics we are attributing neither objectual nor propositional knowledge to him. Maybe when we say someone knows physics, we are attributing a mastery of physics. Thus, knowing physics would be like knowing archery or cookery.


Heath White said...

I think claims like this roughly mean, “Hawking knows most of the propositions accepted by physicists qua physicists [i.e. he knows what they are], and he knows how to use and apply them.” That is, it attributes to Hawking an understanding of a body of propositions.

These propositions need not be true and in fact he need not believe them. I think we could say of someone “Elsie knows astrology” even if Elsie is convinced that astrology is a bunch of hokum. But she knows how astrologers think, what they analyze, what conclusions they draw, and in general how to be an astrologer.

Another way to phrase the same idea would be “Hawking knows all about physics.”

Alexander R Pruss said...

The astrology example suggests that you think Hawking has to know that the propositions are accepted by physicists qua physicists. But we could imagine a lone genius in a faraway land who invents contemporary physics from scratch, and has no concept of physics as such--the idea of disciplines is alien to her, as she sees reality as a unity. She could still count as knowing physics.

Maybe, though, you don't require that one understand the propositions as physics. If so, then let's suppose that she is two hundred years ahead of everybody else, and she has the correct physics, while everybody else is wrong. And our lone genius's development of physics has skipped the mistakes of contemporary physics, so she doesn't know how to use and apply the propositions currently accepted by other physicists.

It's tempting to say that she knows physics because she has an understanding of the body of propositions that constitutes the state of the art, because her lone view is the state of the art. But if to know physics is to understand the body of propositions that constitutes the state of the art in physics, then the existence of such a lone genius makes everybody else be ignorant of physics.

Maybe, though, it should be disjunctive: to know physics is to understand the body of propositions that either constitutes mainstream physics or constitutes the state of the art in physics.

My mastery proposal also has similar problems.

There is another problem with the understanding proposal. Knowledge of physics can be Gettiered. I don't know that understanding can be Gettiered.

Heath White said...

I think there is a certain context-sensitivity to the description. When I was a college freshman I was very good at physics, and people might have said I "knew physics." But I didn't know it like Hawking knows it, or even like my professors knew it, or even like an MIT freshman might have known it. Rather, I "knew physics [in the context of my school's PHY 121 class]".

I think we would pick out the reference class of contemporary professional physicists when describing, say, Hawking. We might describe Newton by saying "he knew physics," taking as the reference class the scientists of his time, but if we update the reference class to today's scientists the description would no longer be true.

Michael Gonzalez said...

Pruss, I think Heath has it right in saying that to "know physics" is to be acquainted with the propositions currently accepted by physicists (or "at the cutting edge of physics").

You imagine the "lone genius" from a faraway land, but that person would never be said to "know physics". They would be said to "come to the same conclusions as Western physics" or some such thing.

As for the "lone genius" who is two hundred years ahead of the game. We would simply say that the correct propositions of physics are something other than we thought, and so only she actually "knows physics". I mean, the existence of a lone genius who has everything right in a field, while everyone else has everything wrong, can have no other effect than that everyone who "thought they knew" actually didn't know.

I think one key element is to distinguish "physics" (or whatever field of inquiry) from the actual explananda. The real world is not physics, even if one of the ways to describe one piece of it accurately happens to be what we call "physics".

Michael Gonzalez said...

To put it in a slightly different way (perhaps a touch Wittgensteinean, but hopefully you'll indulge me), consider "physics" (or any other such field) as a particular way of talking about the world or part of the world. Hawking "knows" physics in that he know how to properly talk as a physicist should talk (or he knows the rules of that particular game). Those rules may change later, and, if Hawking doesn't keep up, he will no longer be said to "know physics". It's akin to your example of "knowing archery", though I would say it's more like "knowing chess". Now, there is a further supposition about physics, that it is (at least approximately) an accurate way to talk about the world. That is to say, when we talk about the world as physicists do, we are approximating the truth of the world (or, at the very least, we will make accurate predictions about the behavior of the world).

My point is that the truth/accuracy of physics, relative to how the world actually is, is a separate level from the degree to which one knows physics itself. To put it another way, one can be perfectly adept at the rules of the game, even if it turns out that that particular game does not properly represent reality.

Dagmara Lizlovs said...

Whether or not Stephen Hawking "knows" physics is a moot point. The real question should be - Does Richard Dawkins, the evolutionary biologist, know biology? From an article in LifeSiteNews:

"Richard Dawkins, a vocal proponent of atheism and the author of The God Delusion, posted a provocative tweet about abortion:

With respect to those meanings of "human" that are relevant to the morality of abortion, any fetus is less human than an adult pig.

Now, when Dawkins typed “any fetus,” he did not mean it. He was not thinking of dolphin fetuses or dog fetuses. What he really meant to say was this:

With respect to those meanings of “human” that are relevant to the morality of abortion, any human fetus is less human than an adult pig."

Full story here:


Will some one please sign this guy up for Taxonomy 101.