.: Ladyman and Ross's Philosophy of Physics: Noumena (1)

Thursday, 24 September 2015

Ladyman and Ross's Philosophy of Physics: Noumena (1)

These pieces are primarily commentaries on the 'Ontic Structural Realism and the Philosophy of Physics' chapter of James Ladyman and Don Ross's book Every Thing Must Go. There are also a handful of references to – and quotes from – other parts of that book.

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Ladyman and Ross (L & R) refer to Kant a few times in Every Thing Must Go. Strangely enough, one time they do so is in response to the various philosophers who've seen “strong affinities” between their own work and Kant's. Nonetheless, L & R tell us “how [their] general account differs from that of Kant”. That fundamental difference is also the main purpose of this short piece.

Every Noumenon Must Go

We can go back to John Locke to see that it may be permanently impossible for us to ascertain the true nature of objects or things (i.e., his “something, I know not what”). In An Essay Concerning Human Understanding, Locke writes:

“…it is impossible for us to know, that this or that quality or Idea has a necessary connexion with a real Essence, of which we have no Idea at all, whatever Species that supposed real Essence may be imagined to constitute.” [IV.vi.5]

That's also partly why Bishop Berkeley turned towards empirical idealism and away from scientific materialism and the scepticism it engendered. In his Three Dialogues between Hylas and Philonous, Berkeley wrote:

“.... the whole issue can be allowed to rest on a single question: is it possible to conceive of a sensible object existing independently of any perceiver? The challenge seems easy enough at first. All I have to do is think of something so remote—a tree in the middle of the forest, perhaps—that no one presently has it in mind. But if I conceive of this thing, then it is present in my mind as I think of it, so it is not truly independent of all perception.” [Dialogue 1]

Thus Kant brought noumena into the debate. Again, the problem of noumena caused various philosophers to embrace (Kantian) transcendental idealism once again – and so did many 19th-century scientists (e.g., Mach, Helmholtz, Boltzmann, Hertz, early Einstein, etc.).

If we come up to date, L & R quote Frank Jackson saying that “we know next to nothing about the intrinsic nature of the world”. Indeed we “know only its causal cum relational nature”.

One way out of this impasse (of noumena and the consequent embracing of idealism) is to become some kind of structuralist. Thus L & R cites Peter Unger arguing that “our knowledge of the world is purely structural”. What's more, Peter Unger also argues that

“things in themselves [i.e., noumena]... are idle wheels in metaphysics and the PPC imposes a moratorium on such purely speculative philosophical toys”.

Kantianism

A semi-Kantian position (needlessly Kantian, according to L & R) is also offered by Mauro Dorato (as quoted by L & R). Dorato writes:

“the concept of unobservable entities that are involved in the structural relations always has some conventional element, and the reality of the entities is constituted by, or derived from, more and more relations in which they are involved.”

I wrote semi-Kantian because that passage begins in a Kantian manner and ends with a structuralism of some kind. The Kantian bit is the following clause:

“... the concept of unobservable entities that are involved in the structural relations always has some conventional element.”

However, the passage ends with these words:

“... the reality of the entities is constituted by, or derived from, more and more relations in which they are involved.”

L & R would simply say: Get rid of these “unobservable entities”. After all, from what Dorato has said it can be concluded that all we've really got are relations and structure. Or in more detail:

Relations don't constitute entities and neither are entities derived from relations. Relations constitute (more) relations and (more) relations are derived from prior relations. It's relations all the way down folks.

To be crude, it can be said that Ladyman and Ross believe that all non-structural realists are to some extent Kantians. Or, at the least, they make the same Kantian mistake.

L & R specifically pick out what they call the “epistemic structural realist” as a Kantian (or quasi-Kantian).

So why 'Kantian'? L & R write:

“... an epistemic structural realist may insist in a Kantian spirit... there being such objects is a necessary condition for our empirical knowledge of the world.”

This is a good description of the noumenal grounding of Kant's metaphysics and indeed his epistemology. You can sum it up with a simple Kantian question:

If there are no noumenal objects (which ground our representations, etc.), then what's it all about?

Even if our representations, models, "posited objects", etc. don't somehow mirror - or simply represent - objects (or if we didn't have the noumenal grounding in the first place), then surely we have precisely nothing. Or as L & R put it (almost quoting Kant word-for-word):

“...there being such objects is a necessary condition for our empirical knowledge of the world.”

So, again, we may not mirror nature or objects; though we must capture something. Then again, how can we represent - let alone mirror - something as strange as Kantian noumena? How would that work?

This is when L & R say: Yes, we capture structure. That won't quite work because the Kantians and quasi-Kantians think they're capturing (if not mirroring) determinate objects. L & R clearly don't think that. That's why L & R appear to make what can be seen as the obvious conclusion. They write:

“.... we shall argue that in the light of contemporary physics... that talk of unknowable intrinsic natures and individuals is idle and has no justified place in metaphysics. This is the sense in which our view is eliminative...”

One can conclude, after reading L & R, that because we can't get at objects in their pristine metaphysically-realist state (we can't mirror objects), then, if that's a necessary truth, we may as well say that “structure is all there is”. This ties in nicely with L & R's position in which Kantian noumena may as well drop out of the picture (as was the case, to some extent, with Bishop Berkeley). Or, as Wittgenstein once put it (though about something else), an object or noumenon is “a wheel that can be turned though nothing else moves with it is not part of the mechanism”[§271].

To put the case very simply, there are two positions which one can adopt here: