Archive for July, 2019

The “C-theory of time” asks if time really has a direction

Monday, July 29th, 2019

I’m sorry, but this article just adds to my impression that Feynman, Weinberg, and Hawking are right about the usefulness of philosophy in science.

Right now I have memories which include the memory of not having memories of some “more recent” events and of, within those memories, having memories which include the memory of remembering even fewer events. It turns out that this pattern of successively smaller sets of memories of memories defines a linear ordering of all my memories. I call the direction towards smaller memory sets my past and the direction from any past memory towards the present the future of that past. (I have no actual knowledge of any future now, but my past memories all had futures and I choose to act as if that pattern “will” continue.)

From those observations alone it does not follow that I will find other beings who have similar patterns of memory, but in fact I have done so (along with evidence that similar beings existed “prior” to my own earliest memory) – and none of us have seen any evidence of beings with a similarly defined sense of past direction that differs from my own. (For many centuries of our shared experience it appeared that we all shared a common “present” but more precise observations have established that that is only possible for beings not moving too rapidly relative to one another. However nothing has been observed which is inconsistent with us all seeing the “past” in the same direction.) A number of physical phenomena are observed to behave symmetrically between past and future but others definitely do not, and in those cases there are fairly simple rules which seem to predict which of two physical situations will be seen as “before” the other.

The upshot of all this (and lots more) is that all of the events that I can remember (or have seen reports of) can be consistently associated with points in a 4-dimensional (but non-Eulidean with +++- signature) “space-time” in which, at each point, there is a (double) cone of “time-like” directions such that many physical phenomena are consistently asymmetric between the two parts of the cone (ie with respect to any version of a “time” coordinate). This is all we mean when we say that “time has a direction”. And it’s true!

Knowledge is a problematic stone-age concept, but are we better off without it?

Tuesday, July 16th, 2019

Philisopher David Papineau argues in a recent Aeon Essay that the idea of knowledge as rigorously justified true belief is “a crude concept we have inherited from our prehistoric ancestors, and it positively handicaps us in our dealings with the modern world.”

Now it is true that the unspecified level of rigorous justification needed to qualify a claim of knowledge makes the concept ambiguous (or at least context-dependent), but the fact that it is an ambiguous refinement of unqualified true belief does not alter the fact that it is indeed a refinement (ie less rather than more “crude”).

And the attempt to refine “true” and “belief” in terms of probability founders, at least for now, on the rock that there is no widely shared correct understanding of what it means. The bizarre and unrealistic example proposed by Papineau to motivate his discussion of probability in the law unfortunately just adds to the confusion – both by its confused analysis of probability and by adding a particularly fraught context (namely common law) for the discussion of what it means to “know” something.

Source: Knowledge is a stone-age concept, we’re better off without it | Aeon Essays

Massimo Pigliucci is wrong about Richard Feynman on beauty and truth in science

Saturday, July 13th, 2019

Do philosophers ever think before they write?

Massimo Pigliucci claims that Feynman is “often quoted” as saying: ‘You can recognise truth by its beauty and simplicity,’ and then uses this claim as the basis for an attack on Feynman’s understanding of what it was that he himself was really doing. Now I have no idea whether the claim that Feynman is “often quoted” that way is true – many people are inaccurately quoted, and the more famous they are the more likely they are to be falsely identified with whatever catchy phrase someone wants to promote. But one would think that a professional philosopher would be above using the fact that someone is “often quoted” as having an opinion to infer that they actually did so – especially since in this case the only supporting evidence comes from one journalist and Pigliucci “could not find other records of Feynman writing or saying it”.

No matter though.  For a philosopher apparently if someone can’t be found to have actually expressed an opinion, then it is sufficient evidence of  having had it that the accused may seen to have admired someone else who did have it – and apparently “we do know” that Feynman admired Paul Dirac who did want theories to be, in some sense, beautiful (and, despite Pigliucci’s complete lack of any attempt to support either of those claims, they are both indeed true). However Dirac’s well-attested reluctance to work on what he considered ugly does not necessarily translate into a conviction that the ugly theory could not actually be true, and despite occasional lapses (as in being initially doubtful of experimental results which  contradicted his and Gell-Mann’s weak interaction theory), Feynman’s ultimate position was exactly the opposite of what Pigliucci claims. His most famous and well-documented position on truth and beauty is in fact as follows:

It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.

Of course beauty is in the eye of the beholder, and to a properly appreciative eye the property of most simply encompassing the largest known range of data is itself the criterion that we identify as beauty in a physical theory. Perhaps this is related to what the poet John Keats meant when he concluded his ‘Ode on a Grecian Urn’ by expressing the identity in both directions.

Source: Richard Feynman was wrong about beauty and truth in science | Aeon Ideas