Kant vs Scientific Rationalism - Do we need the Ding an Sich

Question

I actually like Kant's distinction between noumena and phenomena. But I have a nagging doubt.

If we look at modern physics, appearances can be explained by entities such as atoms, electrons and quarks which are not themselves picturable. I can't say that this reality is the noumenon because by Kant's definition the noumenon cannot be known.

But the approach of scientific rationalism may undermine the idea of the Ding an Sich. Maybe we don't need it. We just keep exploring. Kant had no knowledge of modern science.

Any help here would be much appreciated. I have searched Google in vain. Has anyone written on the matter?

Answer 1

The thing-in-itself isn't the same as theoretical entities, i.e. entities that we cannot directly perceive but can infer from our observation. Kant doesn't, unlike some empiricists, make a sharp distinction here. When he discusses the Third Analogy of Experience in the Critique of Pure Reason he says that, although we cannot directly perceive magnetic fields due to the particular nature of our senses, we can know it perceptually due to an immediate inference from the presence of movement of iron filings. Kant, in other words, would deny that there is any ground for skepticism about our knowledge of magnetic fields just because they cannot be, strictly speaking, directly perceived by us ("directly perceive" is my term, not Kant's - I hope it's intuitively intelligible what I mean).

You significantly underappreciate human ingenuity before "modern science" (let's say, XX-th century science). Atoms and other such entities were postulated long before Kant to explain various phenomena. And, yes, there were some who insisted that this practice is scientifically unsound (although I see no grounds for this) or (a view which is still common) that these are merely 'convenient fictions'. But Kant holds neither of these views.

The thing-in-itself doesn't have anything to do with empirical knowledge. It can be defined the object of knowledge of pure reason, entirely independently of affection by an object which is the cause of experience. And Kant denies such knowledge, metaphysical knowledge, but not scientific explanations which reference entities like atoms etc. which cannot be observed.

It must be said, however, that Kant himself wasn't a proponent of atomism.

Answer 2

"Kant had no knowledge of contemporary science" is I think a more accurate statement than "Kant had no knowledge of modern science," because "modern" science" generally refers to science since the scientific revolution of Newton and his approximate contemporaries in other fields of empirical inquiry. Kant's project was more "grounding" science than inventing something beyond the reach of science with the agenda of keeping philosophy above science (although a case can certainly be made for the latter). I don't think he considered his metaphysics a necessary and hitherto missing piece for the continuing progress of science; I think he considered it a pat on science's back.

But the lasting value of Kant's metaphysics is most evident in what future philosophers have developed off of it. The Ding-an-Sich concept isn't transformed by contemporary science; it's transformed by Hegel, who tries to demonstrate that it's not a thing that exists but a thing in us that defines our investigations of existing things (much like your sentiment that we just keep exploring and finding out more). I recommend Robert Brandom's reading of Kant and Hegel. And also Quine's "Two Dogmas of Empiricism" (that explodes Kantianism as much as anything does, at the analytic/synthetic distinction pivot-point of his theoretical edifice). (Rorty on Quine in Philosophy and the Mirror of Nature for a more readable and less technical rendering of the point.) But my overall point is just that there's a lot more to Kantian metaphysics than a surface reading of the phenomenal/noumenal distinction.

Answer 3

The key to this problem is that the physical sciences produce models of the world; they do not access the world as such. When we talk about subatomic particles — proteins, electrons, neutrons, quarks, or what you will — we are applying concepts defined within a model that largely works to describe the events we see. We cannot see the particles directly, but we can see indirectly see effects on the world that we can attribute to these particles within this model, Therefore the particles are phenomena. In other words:

• We assert that a table is an 'object' because we can place a cup on it, and the cup won't fall through to the floor (as opposed to, say, a hologram of a table). If we were to make a table out of a perfectly transparent material, we could still assert it was an object, because we could still place a cup on it without the cup falling to the floor. The cup not falling as a phenomenal experience that points to the existence of an object.
• We assert that a quark is an 'object' because we can perform certain (highly technical) actions and produce consistent with the model that defined quarks. It doesn't matter that we can't 'see' them directly; like the transparent table, we see an effect that implies the existence of an object.

We don't really 'know' what's happening 'in reality' on the subatomic level. That's all noumena, beyond our grasp. We see certain phenomena; we build models that attempt to encapsulate that phenomena systematically; those models define arguable/argumentative objects that ostensible encapsulate meaningful elements of Ding an Sich. But there is always an insurmountable gap of knowledge between those modeled objects and Ding an Sich itself.