Hume and Kant on Sense Perception

Another round with Ed Buckner who writes,

Meanwhile I continue to struggle through Kant, and I point out what seems to be a fundamental and insuperable difficulty below. (I may be wrong).

Start with Hume, and with what he means by ‘impressions’. As I write, I am looking at what I take to be the black surface of my desk. Note “what I take to be”. Assume that what I take to be the surface is the surface. But what then does Hume mean by an ‘impression’? He says “Those perceptions, which enter with most force and violence, we may name impressions; and under this name I comprehend all our sensations, passions and emotions, as they make their first appearance in the soul”. Ideas are ‘the faint images’ of the impressions in thinking and reasoning.

This is not clear at all. By ‘impression’ Hume means either that which I (perhaps wrongly) take to be the surface of the desk, or something else. Suppose the former. Hume makes it clear that the impression makes its appearance in the soul, and it is clear from everything he says later that an impression is a mental item. But the desk is not a mental item, hence the surface of the desk is not a mental item. Which is absurd.

Or he means the latter. Then the ‘impression’ must be something other than what I take to be the surface of the desk. But I am aware of no such thing. In looking at the desk I am aware of nothing corresponding to a perception which enters “with force and violence”. Nor, when I shut my eyes and think of the surface of the desk, am I aware of anything but a faint memory of seeing the surface itself, rather than the faint image of any ‘impression’.

So both interpretations are problematic. Either my desk and its surface are mental items, which is absurd. Or it is impossible to say what Hume means by ‘impression’. So Hume’s position makes no sense.

I agree with the above analysis. It is clear and convincing. We can also display the problem in my preferred way as an aporetic polyad, in this case a tetrad:

1) Impressions are mental items.

2) The surfaces of physical things are not mental items.

3) What we know when we have sensory knowledge are impressions.

4) We have sensory knowledge of the surfaces of physical things.

These propositions are collectively inconsistent.  So at least one of them must be rejected. As I read Hume, he is committed to (1), (3), and (4), and so he must reject  (2). But this leads to a subjective idealism that both Ed and I find intolerable.  No physical thing such as Ed's desk is a bundle of sense impressions.  Sense impressions are 'in the mind' and no desk or part thereof is in anyone's mind.

The Humean solution is worse than the problem.  Another solution is to reject (3). One might hold a representational theory of mind according to which what we know via the outer senses are, in the typical non-illusory cases,  mind-independent things and some of their parts, but we know them via mental representations.  Enter the epistemic intermediary: contents in the mind mediate between mind and external thing.  

There are other putative solutions such as Husserl's and Butchvarov's. They too have their difficulties. I won't go into them because Ed hasn't read these philosophers.

The next question is whether Kant’s position makes any sense, given that his position here seems closely connected with that of Hume. He speaks of ‘sensible sensations’, ‘the world of the senses’, ‘the field of appearances’ etc etc. What does he mean by these terms? Does he mean the sorts of things that e.g. I take to be parts of material objects? But then it seems to follow from everything else he says that either material objects are mental items, or that I am wrong in thinking that what I take to be part of a material object, is in fact such. Both positions are absurd.

Have I misunderstood Kant? 

To assimilate Kant to Hume is a mistake. There are many crucial differences between the two. For one thing, Kant is not a subjective idealist. He does not hold that physical things are bundles of impressions.  He would reject (3) in the tetrad above.  To explain this is impossible in a few sentences.  I refer Ed to Kant's Letter to Marcus Herz, 21 February 1772 which may help. 

There is also the following excerpt from a different entry:

Kant

 

I think Ed is wrong above about Kant.  For Kant, the pure is the opposite of the empirical. Every concept is either pure or empirical and no concept is both. A pure concept is one that is not drawn from experience, ein solcher der nicht von der Erfahrung abgezogen ist, but originates from the understanding in respect of both form and content, sondern auch dem Inhalte nach aus dem Verstande entspringt. The form of all concepts, including pure concepts, arises from reflexion Reflexion, and thus from the understanding. Empirical concepts arise from the senses, entspringen aus den Sinnen,  by comparison of the objects of experience. Their content comes from the senses, and their form of universality, Form der Allgemeinheit, alone from the understanding.

 

If Buckner is telling us that Kant's pure-empirical distinction runs parallel to Zabarella's first intention-second intention distinction, then that can't be right. For Zabarella's animal and human being, which are first intentions for him, count as empirical concepts for Kant. 

 

Any comparison of Zabarella (1533-1589) the Aristotelian and Kant is bound to be fraught with difficulty because of the transcendental-subjective turn of modern philosophy commencing with Descartes (1596-1650).  For Aristotle, the categories are categories of a real world independent of  our understanding; for Kant, the categories are precisely categories of the understanding (Verstandeskategorien) grounded in the understanding both in their form and in their content.  The categories of Aristotle are thus objective, categories belonging to a world to be understood, and not subjective, categories whereby a mind understands the world.

 

Pure Concepts of Reason as Limit Concepts

 

Kant also speaks in his Logic and elsewhere of Ideas which are pure concepts of reason, Vernunft, and not of understanding, Verstand. Die Idee ist ein Vernunftbegriff deren Gegenstand gar nicht in der Erfahrug kann angetroffen werden. (Logik, sec. 3)  The objects of these pure concepts of reason cannot be known by us because our form of intuition, Anschauung, is sensible, not intellectual. We can know only phenomena, not noumena. Among these Ideas, which are plainly limit concepts, are God, the soul, the world-whole, and freedom. And they are not merely negative limit concepts. Free will, for example, is objectively real despite its not being obejctively knowable. But more on this later.

Comments

[O.Z.]

I read this 2020 post again with interest.

In the comments section I identified the following five claims that you made:

(1) The sun is a phenomenon.
(2) Phenomena are “out there among things”
(3) The sun (together with the stone) is “out there among things”.
(4) The sun warms the stone (which implies it causes the stone to warm)
(5) The necessary connection is not out there among the things

I argued that these are mutually inconsistent. You replied that I did not understand Kant (to which I agreed) but that does not resolve the problem that the five claims are inconsistent.

[OZ]

My position remains that Kant, so far as I understand him, is a good old-fashioned subjective idealist. What Berkeley calls ‘ideas’, and Hume calls ‘impressions’, Kant calls ‘representations’ (Vorstellungen).

You say I simply haven’t understood Kant. Possibly, but my understanding is a respectable one in the literature of Kant interpretation. https://plato.stanford.edu/entries/kant-transcendental-idealism/#FedeGarvRevi “On one plausible reading of these passages, Kant is claiming that all there is for objects in space to exist is for us to have experiences as of objects in space. Consequently, if we did not exist, or did not have such experiences, these objects would not exist. The Feder-Garve interpretation of transcendental idealism is not without some merit.“

As I mentioned, I am now looking in detail at the Critique, and its roots in Kant’s strange book on Logic.

[OZ]

Regarding my first comment, it occurred to me that the apparent contradiction could be resolved by distinguishing "thing outside us" as either (i) a thing that exists distinct from us or (ii) a thing that merely is a part of 'outer appearance'. The first is external in Kant's transcendental sense, the second is an 'empirically external object'. See (A373).

So in your (3) the sun is "out there among things" in the second sense, i.e. it is empirically external.

Was that your intention?

The problem I identified remains, however.

[OZ]

I can't remember if I posted what is below. If so, please ignore.

------------------
On the business of Kant interpretation, when I look at the black surface of my desk, then (1) while I agree we could say there is something intuited (angeschauet) by me, which is an object of experience (Erfahrung), nevertheless (2) this object of experience, is manifestly neither an appearance (Erscheinung), nor a representation (Vorstellung).

For the visible surface of a desk is not an appearance – it is the surface of a desk – nor for the same reason is it a representation. (Of course I could draw a picture of a desk on the surface of the desk, and that would doubtless be a representation. But the surface of the desk itself is not a representation of the surface of a desk).

It is also entirely false to claim that the surface of the desk has “no existence grounded in itself (an sich)” outside my thought. The desk (and its visible surface) is a per se being, it exists ‘in itself’ whether or not I am looking at it.

But Kant says otherwise. A491/ B519.

You will certainly object that there are two things I am aware of here, the black surface of the desk, and the appearance or sensible intuition or representation of the black surface of the desk. I deny this. All that I am aware of is the black surface of the desk, and the existence of anything else would need to be demonstrated beyond all doubt.

What you need is a sort of ontological argument for ‘sensible intuitions’. I haven’t seen one.

[BV]

>>My position remains that Kant, so far as I understand him, is a good old-fashioned subjective idealist. What Berkeley calls ‘ideas’, and Hume calls ‘impressions’, Kant calls ‘representations’ (Vorstellungen).<<

There is no way this can be correct if you consider everything that Kant says. What you could say, however, is that Kant's texts allow of no one unitary interpretation.

In my Ph.D. dissertation I maintained that this is the case with respect to K's doctrine of the transcendental unity of apperception.

The quotation above is ambiguous. Are you saying that the only way you could understand Kant is by understanding him as a subjective idealist, or that Kant is a subjective idealist? Is your remark autobiographical or is it about Kant's doctrine? If the former, then I say OK. If the latter, I say you are wrong.

[oz the ostrich]

There are a number of "proof texts" that support my view. However my argument is more fundamental, and begins with my claim that, when I open my eyes and look, the visible surface of the desk appears before me. To that extent the surface is an appearance: it is the subject of the verb ‘appears’. But Kant says that this ‘appearance’ is nothing in itself, but only a mere modification or foundation of my ‘sensible intuition’ (A46/B63]. But that is false: the visible surface of the desk is not a modification of my ‘sensible intuition’, for it is the surface of a desk, not a modification of anything that is mine.

[oz the ostrich]

The root of the difficulty of interpretation is the verbal noun ‘appearance’ (Erscheinung). Does it denote a relation between the visible surface and my sight? I open my eyes and the visible surface appears. So there is an appearing. Does Kant mean an appearing, or does he mean some particular sort of object? He says (A20/B34) “The undetermined object of an empirical intuition is called appearance.” (Der unbestimmte Gegenstand einer empirischen Anschauung heißt Erscheinung). That form of words suggest the latter.

He adds “that which allows the manifold of appearance to be intuited as ordered in certain relations I call the form of appearance”. What is the ‘manifold of appearance’? I am looking at the surface of my desk now covered with papers, books, and a pocket chess board. Does he mean that all the coloured surfaces I see are a ‘manifold of appearance’? And is the spatially ordered chequerboard pattern a ‘form of appearance’? It is the objects themselves, the surfaces of bodies, which have that spatial order, so why does Kant not say so?

Also, how on this interpretation does Kant’s view differ from the traditional Aristotelian view about space (and time)?

Space and time also belong to this class of [continuous] quantities. Time, past, present, and future, forms a continuous whole. Space, likewise, is a continuous quantity; for the parts of a solid occupy a certain space, and these have a common boundary; it follows that the parts of space also, which are occupied by the parts of the solid, have the same common boundary as the parts of the solid. Thus, not only time, but space also, is a continuous quantity, for its parts have a common boundary. (Categories 5a 5)

[BV]

You didn't respond to what I said at 4:31. Do so, and we can proceed.

[oz the clever ostrich]

Sorry I thought it was obvious from what I said. He is clearly a subjective idealist.

[oz the perceptive ostrich]

From NKS' commentary: “Frequently Kant's argument implies this distinction [between intuition and appearance], yet constantly he speaks and argues as if it were non-existent. We have to recognise two tendencies in Kant, subjectivist and phenomenalist. When the former tendency is in the ascendent, he regards all appearances, all phenomena, all empirical objects, as representations, modifications of the sensibility, merely subjective. When, on the other hand, his thinking is dominated by the latter tendency, appearances gain an existence independent of the individual mind. They are known through subjective representations, but must not be directly equated with them. They have a genuine objectivity.”

Yes, I am aware that this NKS view is regarded by some modern commentators as outdated.

[Tom Tillett]

I hate to intrude between you two. However, I have to say that Kant is not a subjective idealist. This is so not least because Kant knew what a subjective idealist philosophy was - most assuredly better than the three of us - and he clearly intended to write something else. Now, you can say his philosophy failed or that it would have been better if he followed through on some of the subjective idealist notions in his work. But none of that changes the fact that his concepts of the noumena and things in themselves, which are fundamental to the first Critique, mark his philosophy as attempting to preserve the reality of the world outside of an experience. Get rid of those concepts in Kantian philosophy, and yes, you've got some sort of subjective idealism. In fact, that is precisely what some later philosophers did. See German Idealism. But retain them, as Kant insisted, even as some kind of limit concepts, and you have some version - a rather brilliant version, actually - of empirical realism.

[BV]

No intrusion, Tom. Thank you for your comment. I am happy to agree with you.

>> But none of that changes the fact that his concepts of the noumena and things in themselves, which are fundamental to the first Critique, mark his philosophy as attempting to preserve the reality of the world outside of an experience. Get rid of those concepts in Kantian philosophy, and yes, you've got some sort of subjective idealism.<<

That's right. Kant's project is to secure the objective/intersubjective validity of our knowledge of nature in the teeth of Hume's skepticism. Whether he succeeds in doing so is a further question. Ed does not appreciate what Kant is trying to do.

But I would not say that German idealism sank back into a subjective idealism. It would not be difficult to show this with respect to Fichte, Schelling, and Hegel.

Schopenhauer did revert to an absurd subjective idealism, a physiological idealism according to which "The world is my representation" and that representation is in my brain!

Obviously, the physical world in all its vastness cannot be parasitic for its existence on a measly proper part of the physical world.

[oz]

"Kant knew what a subjective idealist philosophy was" - there is no evidence that Kant read Berkeley (or Hume) in English.

[oz]

"The position of all genuine idealists from the Eleatics to Berkeley is contained in this formula : 'All cognition through the senses and experience is nothing but mere illusion, and only in the ideas of pure understanding and Reason is there truth.' The fundamental principle ruling all my idealism, on the contrary, is this: 'All cognition of things solely from pure understanding or pure Reason is nothing but mere illusion and only in experience is there truth." (Kant, Prolegomena)

That is a bizarre interpretation of Berkeley.

[oz]

I think we should all agree on what counts as ‘subjective idealism’. I characterise it as the view that the objects we commonly take to be physical objects are in some way, or wholly, mind dependent. This a reasonable interpretation of Kant.

[oz the ostrich]

Assuming we agree with my definition of ‘subjective idealism’, here is my argument that Kant is a subjective idealist.

1. Kant claims that perceiving involves the immediate awareness of certain mental items.
2. When I look at the visible surface of this desk, all I am immediately aware of is the visible surface of this desk.
3. Therefore (if Kant is right) the visible surface of this desk is a mental item.
4. If what is true of me is true of everyone, then what we take to be physical items (visible surfaces e.g.) are mental items.

Proof of (1): Therea are many passages, but see e.g. (A50/B74) where he says that objects are ‘given’ (gegeben) to us via representations (Vorstellungen) or impressions (Eindrücke), and that these representations are in (literally ‘of’) the mind (des Gemüts). See also B41 where he says that a representation is ‘immediate’ (unmittelbare), and that immediate representation is ‘intuition’ (Anschauung).

(2) is my own testimony, but I assume this matches yours.

[Tom Tillett]

I am a bit late on this conversation; I have a full time job. So let me respond first to Bill on German Idealism: Thanks for the comments. I really did mean to qualify that quickie reference, like I did in the previous sentence. It should have read 'See some of the German Idealists.' That said, I do have a general suspicion about Hegelian Idealism arising from the Kierkegaardian critique, which probably relates more to the disciples of Hegel in Denmark than Hegel himself: that the actuality they profess to incorporate in their philosophy is not the factual being of actuality, but an actuality already taken up into the being of thought. If that critique is in any way coherent, then it would seem that Hegelian Idealism (of Denmark?) is stuck in the subjective.

[Tom Tillett]

Oz: I am playing these days with a different definition of subjective idealism: it is any philosophy that does not incorporate a real distinction between the being of existence and existing things (factual being) and the being of thought. But I am comfortable for these purposes using your definition (for now).

I am years out from getting down into the weeds of Kant's terminology for perception, intuition, representations, and the like. But I don't think we need to. It seems to me that what you have arrived at by #4 is a physical object that is an appearance, aka phenomena. And that is indeed for Kant an item 'in some way … mind dependent.' So, if that's all there was to Kant he would be liable to the claim of being a subjective idealist per your definition. But Kant insists that this desk that you so clearly see is only an appearance, that the real thing in itself is there but unknowable by beings like we are. It is this insistence of Kant that takes him out of the subjective idealist realm and into - as I said - a version of empirical realism.

By the way, Kant's insistence on the concepts of the noumena and the thing in itself has great significance for where he wants to take his philosophy, especially in the 2nd Critique. But that is not relevant right now.

[OZ]

Thanks Tom