Realism and its competitors

Scepticism, idealism, phenomenalism

“Perceptual Subjectivism”

• Bonjour gives the term “perceptual subjectivism” to the conclusion of the argument from illusion .

• Perceptual subjectivism is the disjunction of two different views: the sense-datum theory and the adverbial theory. (And direct realism too, as Huemer understands it.)

Relevance to epistemology

1. (Assuming that perceptual subjectivism is true) Can beliefs concerning the external material world, and the objects that it allegedly contains, can be justified on the basis of our immediate sensory experience?

2. If they can, then how?

Perceptual subjectivism and scepticism

• E.g. does perceptual subjectivism lead to scepticism?

• (Hume seems to think so.)

Representative Realism

• Realism:

– There is an external world that causes our sensations and our beliefs about the external world.

– We can have (approximate and fallible) knowledge of the external world.

• Representative:

– The “objects” in our conscious awareness (e.g. in the visual field) are internal representations, not external objects.

Descartes’ rationalist approach

• Descartes was a perceptual subjectivist, and also a representative realist.

• He used reason to prove that the senses are reliable:

1. He proved his own existence “I think, therefore I am”

2. He realised from this proof that anything intuitively obvious (“clear and distinct”) must be true.

3. He proved that his creator, the designer of his minds and senses, was a perfect being (not a deceiver).

4. He inferred that his senses can be trusted.

Thomas Reid disagrees

“The sceptic asks me, Why do you believe the existence of the external object which you perceive? This belief, sir, is none of my manufacture; it came from the mint of Nature; it bears her image and superscription; and, if it is not right, the fault is not mine: I even took it upon trust, and without suspicion. …Thomas Reid, Inquiry into the Human Mind, (1764) Chapter 6, Section 20.

… Reason, says the sceptic, is the only judge of truth, and you ought to throw off every opinion and every belief that is not grounded on reason. …

… Why, sir, should I believe the faculty of reason more than that of perception?—they came both out of the same shop, and were made by the same artist; and if he puts one piece of false ware into my hands, what should hinder him from putting another?”

Locke agrees with Reid

“… The best assurance I can have, the best my faculties are capable of, is the testimony of my eyes; they are the proper and sole judges of this thing …

The testimony of our senses that there are things existing in nature gives us as much assurance of this as we are capable of, and as much as we need.”

(Locke, Essay Concerning Human Understanding, Book IV, Chapter xi)

Locke’s extra arguments for realism

1. Those lacking some sense organs also lack the corresponding ideas

2. Sensory ideas are involuntary3. Some sensory ideas (but not imagined ideas) are

accompanied by pain.4. Sensory ideas are orderly and consistent.

• BonJour (and probably Locke) thinks that facts #2 and #4 are best explained by the view that there is a stable external world causing the sensations.

• Alternative explanations?

Hume attacks direct realism

• The table that we see seems to shrink as we move away from it; but the real table that exists independently of us doesn’t alter; so what was present to the mind wasn’t the real table but only an image of it. These are the obvious dictates of reason; and no-one who thinks about it has ever doubted that when we say ‘this house’ and ‘that tree’ the things we are referring to are nothing but perceptions in the mind—fleeting copies or representations of other things that are independent of us and don’t change.

• How can philosophy justify the claim that “there are external objects that our images represent”?

1. Philosophy can no longer rely on the idea that natural instincts are infallible and irresistible, for those instincts led us to a quite different system that is admitted to be fallible and even wrong.

2. And to justify ·the external-object part of· this purported philosophical system by a chain of clear and convincing argument—or even by any appearance of argument—is more than anyone can do.

[E.g. Descartes failed.]

Hume attacks representative realism

• N.B. Points 1 and 2 roughly respond to what (1) externalists and (2) internalists want to say in response to Hume’s sceptical challenge.

• Is Hume right that our natural instincts cannot be trusted? E.g.

– Do tables appear to shrink as we move away from them?

– Can we trust our natural instincts only if they’re infallible?

Internalism vs. externalism

• Internalists say that knowledge requires justification from an internal, 1st person perspective. I must be consciously aware of evidence that proves my belief.

• Externalists say that knowledge requires justification (or “warrant”) from an external, 3rd person perspective. I don’t have to be aware of evidence supporting my belief. Warrant depends only on a good and proper connection between my belief and reality that exists in fact, i.e. from a 3rd person perspective.

Hume’s scepticism (point 2)“By what argument can it be proved that the perceptions of the mind must be caused by external objects that are perfectly distinct from them and yet similar to them (if that were possible), rather than arising from the energy of the mind itself, or from the activities of some invisible and unknown spirit, or from some other cause still more unknown to us? ...Where shall we look for an answer to it? To experience, surely, as we do with all other questions of that kind. But here experience is and must be entirely silent. The mind never has anything present to it except the perceptions, and can’t possibly experience their connection with objects. The belief in such a connection, therefore, has no foundation in reasoning because the reasoning would have to start from something known through experience.” (p. 2)

• In order to learn from experience about what causes what, Hume says that you have to experience “both ends” of the causal relation.

• E.g. in order to learn from experience that fire causes smoke, you have to experience fire-smoke … fire-smoke … fire-smoke, etc. repeatedly.

• If you just experience smoke … smoke … smoke, then you can’t know what the cause of the smoke is.

E.g. can we trust telescopes?

Regress of justification problem

1. In order to know something, I must have a good reason for believing it.

2. Any chain of reasons must have one of the following structures: Either(a) it is an infinite series, (b) it is circular, or(c) it begins with a belief for which there are no further reasons. But,

3. I cannot have an infinitely long chain of reasoning for any of my beliefs.

4. Circular reasoning cannot produce knowledge.

5. Nor can I gain knowledge by structure 2c.

6. Therefore, I cannot know anything.

Problem of the criterion

• Imagine there were a community in which use of the Magic Eight Ball was an accepted method of arriving at conclusions. Suppose you meet one of these eight-ball reasoners, and you ask him why he believes that the eight ball is a reliable informant. He swiftly takes out his Magic Eight Ball, says, “Are you reliable?” and turns it over. Suppose a definite “Yes” answer appears, and the eight-ball reasoner triumphantly declares that the reliability of the eight ball has been established. Would this be legitimate?

• (Michael Huemer, p. 11)

• “Now consider an analogous case. Suppose some skeptic comes along and asks you why you believe the senses to be reliable. Why do you think that, when you seem to see, hear, or feel things, this is a reliable indicator of the way things really are, in the external world? How would you respond?”

• Is there anything you could say that would avoid the same vicious circularity that the eight-ball reasoner committed?

Berkeley: “objects” as God’s ideas

• Berkeley’s idealism is a lot like the Cartesian demon scenario, except that it doesn’t involve any deception according to Berkeley.

• There are no ‘material substances’, i.e. objects that exist, and have properties, independently of anyone perceiving them, and yet are able to cause us to form accurate ideas of them.

• Ordinary objects, such as chairs and tables, are actually ideas in the mind of God that are transmitted somehow to our minds. The world consists only of minds (divine and human) and their ideas.

• Berkeley argues that his idealism is in accordance with common sense, even more than Locke’s representational realism.)

• For example, Berkeley thinks that tomatoes really arered.

• In order for the external world to be suitably solid and objective, e.g. for objects to continue to exist even when no human is perceiving them, a super-perceiver (God) is required.

• The need for God is an advantage of the theory, for (Bishop) Berkeley.

God in the Quadby Ronald Knox

There was a young man who said, "GodMust think it exceedingly oddIf he finds that this treeContinues to beWhen there's no one about in the Quad."

REPLYDear Sir:Your astonishment's odd:I am always about in the Quad.And that's why the treeWill continue to be,Since observed byYours faithfully,GOD.

Berkeley’s argument

1. “sensible things” = things that are perceived immediately by the senses.

So “sensible things” are ideas.

(Note that Berkeley – Philonous— believes that the senses “make no inferences”.)

2. Sensible objects are combinations of sensible qualities. (Bundle theory of internal objects.)

E.g. a snowball-idea is the combination of whiteness, coldness, roundness, firmness, etc.

3. The reality of sensible things consists in being perceived. The notion of a pain, for example, that isn’t felt by anyone, is silly.

For sensible objects, esse est percipi (to be is to be perceived.

4. Then Hylas (“matter”) objects, saying that real objects must exist independently, without any need to be perceived.

Philonous responds with Lockean arguments that some qualities cannot exist outside the mind. Heat, for example, is continuous with pain, and pain is only in minds. “the intense heat immediately perceived is nothing distinct from a certain sort of pain”.

5. Hylas yields, agreeing that heat and cold are not in the objects, but are only sensations in our minds. But there are other qualities that do exist objectively, e.g. tastes and sounds. Real sound is nothing but a certain motion of the air.

6. Eventually Hylas accepts Locke’s full list of secondary qualities, including colours, tastes, smells and sounds.

But still, like Locke, Hylas continues to believe that shape, size (“extension” and “figure”), texture etc. are primary, and exist in the object, not just in a perceiving mind.

7. Now the main argument. Philonous tries to show that the same arguments can be applied to (what Locke considers to be) primary qualities, such as figure and extension (shape and size).

Philonous appeals to mites. The foot of a mite will seem to be large to a mite, yet tiny to us. So size is subjective.

• Note the general pattern of argument here:

– If a quality depends on the observer, i.e. its appearance varies with the type of observer (e.g. mite or human) or with the way in which it’s perceived, then the quality is subjective, and exists only in the mind.

• Is this pattern reasonable?

8. Also, as we approach and recede from an object, its visible size varies.

[Berkeley might have added, but didn’t, that a circular pond appears circular only from directly above. From most angles its apparent shape is an ellipse.]

9. Also, the same object that is smooth to the naked eye is rough when viewed through a microscope.

So textures, a supposed primary quality, also depend on the observer.

10. In other words, all qualities turn out to be secondary. There are no primary qualities at all. None which can be supposed to exist independently, without being perceived.

11. As a last resort, Hylas appeals to the notion of substratum.

The idea of ‘substratum’ is that the qualities of an object need to belong to something. They need to be properties of something. They’re not just a bundle. That “something” that has the properties is the substratum.

You can picture the properties as sewing pins. The substratum is then the pincushion that the pins are stuck into.

Substance vs. properties

E.g. The cheese is a substance, but the holes are not substances. They’re just modifications (properties) of the cheese.

12.The substratum is not “sensible” (we don’t sense it).

Hylas says “I conclude it exists because qualities cannot be conceived to exist without a support”. (p. 103)

Later (p. 104) “I find that I know nothing of it”.

“Is it not a great contradiction to talk of conceivinga thing which is unconceived?” Philonousresponds.

Another argument

13. “… no idea nor anything like an idea can exist in an unperceiving substance …”

“can anything be like a sensation or idea, but another sensation or idea?”

The correspondence between ideas and non-mental things strikes many as problematic. For example, the correspondence of propositions to objective facts or actual states of affairs.

Is realism excessive?

“How could there be truths totally independent of minds or persons? Truths are the sort of things persons know; and the idea that there are or could be truths quite beyond the best methods of apprehension seems peculiar and outre and somehow outrageous. What would account for such truths? How would they get there? Where would they come from? How could the things that are in fact true or false—propositions, let’s say—exist in serene and majestic independence of persons and their means of apprehension? How could there be propositions no one has ever so much as grasped or thought of?”(Alvin Plantinga, “How to be an anti-realist”, Proceedings and Addresses of the American Philosophical Association, Vol. 56, No. 1. (Sep., 1982), pp. 47-70.

40

Augustinian theism

• the view that abstract entities such as universals and possible states of affairs depend for their existence on the divine mind.

“The ideas are certain archetypal forms or stable and immutable essences of things, which have not themselves been formed but, existing eternally and without change, are contained in the divine intelligence. They neither arise nor pass away, but whatever arises and passes away is formed according to them.” (Augustine, De Ideis 2)

41

• Also accepted by (e.g.):

– Aquinas

– Leibniz

– Robert Adams

– Thomas Morris and Chris Menzel

– Alvin Plantinga

“Even if there were no human intellects, there could be truths because of their relation to the divine intellect. But if, per impossible, there were no intellects at all, but things continued to exist, then there would be no such reality as truth.”(Aquinas, De Veritate Q. 1, Article II, Reply).

“the nature of a circle, and the fact that two and three make five, have eternity in the mind of God”(Aquinas, Summa Theologiae Ia, q. 16, a. 7, obj. 1 and reply).

42

Problem for Berkeley

Minds, or spirits, are (in some sense) mind-independent substances for Berkeley. When God creates humans, for example, he does more than just have an idea. He has to “concretise” that idea somehow – make it active.

We aren’t just ideas in the mind of God. So why can’t there be other mind-independent substances?

• If we ask Berkeley what makes a mind “concrete” in a way that ideas are not, what would he say?

• “Something, I know not what?”

• After all, we don’t perceive minds, just ideas …

• Can Berkeley have a clear conception of what the mind really is?

• “Is it not a great contradiction to talk of conceiving a thing which is unconceived?”

Problem

• What’s the difference (for Berkeley) between the real world and the possible worlds?

• “It is important not to confuse the actual world with the World. The actual world is a mere specification, a description of a way for things to be. It has only the kind of abstract reality that belongs to a story or a scenario or a computer program. The World, however, is not a description of a way for things to be: it is, so to speak, the things themselves. If it is an individual thing, it has you and me and every other individual thing as parts.”

• (Peter van Inwagen, Metaphysics, 4th ed., Ch. 6)

Locke vs. Berkeley

• Which theory better explains the facts about sensation that Locke listed?

1. Those lacking some sense organs also lack the corresponding ideas

2. Sensory ideas are involuntary

3. Some sensory ideas (but not imagined ideas) are accompanied by pain.

4. Sensory ideas are orderly and consistent.

Phenomenalism

• “a version of idealism” (BonJour, p. 125)

• John Stuart Mill: material objects are nothing but “permanent possibilities of sensation,”

• “The crucial thing to see is that what Mill and the other phenomenalists are saying is that there are no independently existing objects that are responsible for the possibilities of sensation or the obtainability of sense-data; the actuality and obtainability of sense-data are all there is to the physical or material world. These facts are the bottom line, not explained or explainable by anything further.” (p. 126)

BonJour’s confession …

• Phenomenalism is in fact one of those occasional (some would say more than occasional) philosophical views that is so monumentally bizarre and implausible, at least from anything close to a common-sense standpoint, as to perhaps make it difficult for some of you to believe that it really says what it does—and even more difficult to believe that such a view has in fact sometimes been widely advocated and (apparently) believed, indeed that it was arguably the dominant view concerning the problem of the external world for a good portion of the last century … (p. 127)

Phenomenalism

• Talk of external objects can be systematically translated into talk about actual and possible sense data.

• A material object is not a mysterious something “behind” the appearances, i.e. a cause of the sense data.

• (As Hume argued, such a mind-independent cause of sense data would be unknowable, and in fact the very concept is unintelligible.)

Big problems with phenomenalism

1. Rightly or wrongly, we do believe in mind-independent material objects. Phenomenalism gets the meanings of statements about material objects dead wrong.

2. What explains the agreed fact that sense-data are stable and orderly? For the phenomenalist, it’s a brute fact, incapable of being explained.

Technical difficulties with phenomenalism:

• In specifying the meaning of a statement about an external object, one cannot appeal to other external objects. It all has to be done using sense-data. Is this possible?

• What about statements about objects in the distant past?

• Chisholm’s objection involving sensory abnormalities

• Phenomenalism leads to solipsism?

Can RR be defended?

• Can we have knowledge of causation, other than from experience of “both ends”?

• There seem to be examples of this! (E.g. the chemical constituents of stars.)

• Is IBE (inference to the best explanation) the answer?

– Requires a priori knowledge?