Philosophy 5550


Seminar 1 - Skepticism - Part 2

Michael Huemer on Skepticism – Continued

Chapter III of Skepticism and the Veil of Perception: “Easy Answers to Skepticism”

1.  Is Skepticism Self-Refuting?


1.  Mike Huemer points out that regardless of what may be the case with regard to radical, universal skepticism, skepticism about the external world is not self-refuting.

2.  He then goes on to argue that radical, universal skepticism is self-refuting, not because it is self-contradictory, but because “its truth would entail our lack of justification for asserting it.”  (28)

3.  The gist of Mike Huemer's argument is that the universal skeptic will not be able to claim either that his or her premises are justified, or that, given those premises, the conclusion is justified.

4.  A crucial point is that the universal skeptic cannot even advance a reductio ad absurdum argument, since this presupposes that deductive reasoning is a justified method of arriving at beliefs.

Comment

I think that Mike Huemer is right about radical, universal skepticism.

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5.  One conclusion that Mike Huemer wants to draw is that the first two skeptical arguments considered in the previous chapter are self-refuting, since they are defenses of universal skepticism.

Comments

(1) Those two arguments can be recast, however, so that they are defenses not of radical, universal skepticism, but of skepticism with regard to the external world.

(2) This can be done, in the case of the infinite regress argument, by holding that some propositions expressing necessary truths can be non-inferentially justified.

(3) Similarly, in the case of the "problem of the criterion" argument, one can hold, first, that self-contradictory propositions are necessarily false, and, secondly, that the form of a proposition is something that one can directly recognize.

(4) Moreover, there is a form of skepticism that is more modest, but still extremely threatening: it is what might be referred to as universal skepticism about the justification of beliefs involving all contingent propositions. This view seems to me clearly not self-refuting, since this thesis, if true, is a necessary truth, not a contingent one, and the skeptic can use arguments that involve only necessary truths to attempt to prove that there is not contingent proposition that one can ever be justified in believing. 

2. The G. E. Moore Shift


G. E. Moore's Formulation of his Argument

In his essay “Hume's Theory Examined,” G. E. Moore discusses an argument for external world skepticism that is based upon what he refers to as “Hume's principles", and he offers the following argument against Hume's principles:

“It seems to me that, in fact, there really is no stronger and better argument than the following. I do know that this pencil exists; but I could not know this, if Hume's principles were true; therefore, Hume's principles, one or both of them, are false. I think that this argument really is as strong and good a one as any that could be used: and I think that it really is conclusive In other words, I think that the fact that if Hume's principles were true, I could not know of the existence of this pencil, is a reduction ad absurdum of those principles.”                                        (HTE, pp. 119-20)

Moore then goes on, first of all, to argue that one could not have any knowledge at all unless there were some propositions of whose truth one had immediate (or non-inferential) knowledge, and then he claims that among the immediate knowledge that it is possible to have is, for example, knowledge that one is presently holding and seeing is a pencil.

But is it true that one can have immediate knowledge of the existence of physical objects? This might after all be challenged by an argument claiming that immediate knowledge is restricted to propositions about things of which one can be directly aware, and it might be claimed that one can only be directly aware of the contents of one's own mental states.

One way of responding to this objection is by holding that one can be directly aware of physical states of affairs, and as we shall see when we turn to chapter IV of Mike Huemer's Skepticism and the Veil of Perception – “A Version of Direct Realism” – Mike Huemer holds that one can be directly aware of physical states of affairs.  But G. E. Moore does not, so that type of reply is not available to him.  His response is instead as follows:

“But whether the exact proposition which formed my premise, namely: I do know that this pencil exists; or only the proposition: This pencil exists; or only the proposition: The sense data which I directly apprehend are a sign that it exists; is known by me immediately, one or the other of them, I think, certainly is so. And all three of them are much more certain than any premiss which could be used to prove that they are false; and also much more certain than any other premiss which could be used to prove that they are true. That is why I say that the strongest argument to prove that Hume's principles are false is the argument from a particular case, like this in which we know of the existence of some material object.  (HTE, pp. 125-6)

Huemer's Defense of the G. E. Moore's Argument


    Mike Huemer discussion of the Moorean defense against skepticism is as follows.

1. Mike Huemer points out that G. E. Moore actually responds to Hume's argument for skepticism – in “Hume's Theory Examined” (in Some Main Problems of Philosophy).

2.  Mike Huemer's goal in this section is to set out an argument to show that skeptical arguments cannot succeed against common sense beliefs.

3.  Earlier, common sense beliefs were defined as follows:

"i.      They are accepted by almost everyone (except some philosophers and some madmen) regardless of what culture or time period one belongs to.

 ii.     They tend to be taken for granted in ordinary life . . ..

 iii.    If a person believes a contrary to one of these propositions, then it is a sign of insanity."   (18)

Comments

(1) It is very important to notice that Mike Huemer's definition of common sense beliefs is not a definition of what it is to be a common sense belief at some specific time t.  Thus he does not say, for example, that for the belief that p to be a common sense belief at time t, p must have been accepted by almost everyone at every time up to and including time t.  What he defines is a non-temporally-indexed concept of “common sense belief", according to which to be a common sense belief, p must be accepted by almost everyone at every time, past, present, and future.

(2) To know (or be justified in believing), then, for example, that the belief that there are rocks is a common sense belief, one must know (or be justified in believing) that the belief that there are rocks will be accepted by almost everyone in the future.

(3) The fact that the belief that p has been accepted by almost everyone at every time up to and including time t does not therefore entail that p is a common sense belief.  Does knowing that p has been accepted by almost everyone at every time up to and including time t justify one in believing, at time t, that p is a common sense belief?  If not, what more is required?

(4) Suppose that p has been accepted by almost everyone at every time up to and including time t, and will, as things turn out, also be accepted by almost everyone at every time in the future, whereas while q has been accepted by almost everyone at every time up to and including time t, it will not, as a matter of future fact, be accepted by almost everyone at every time in the future.  Is it necessarily the case that there must be something that enables one to be justified in believing, at time t, that p will be accepted by everyone in the future, whereas q will not be?  If so, what would that be?

(5) The underlying questions, in short, are these:

(a) First of all, among the beliefs that have been accepted by almost everyone at every time up to and including the present moment, can one tell which of those are common sense beliefs and which are not, and thus, which of those beliefs have the highest level of initial plausibility, and which do not?

(b) If one can tell, how can one do this? How can one distinguish between those beliefs that will be accepted by almost everyone at all future times, and those that will not? 

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4.  The defense against skepticism that Mike offers here involves the following argument:

"1.  Given a conflict between two beliefs, it is rational to reject the less initially plausible one, rather than the more plausible one.

2.  Common sense beliefs have the highest level of initial plausibility.

3.  Philosophical theories do not.

4.  Therefore, given a conflict between a philosophical theory and common sense, it is rational to reject the philosophical theory, rather than common sense."                        (SVP, p. 36)

5.  In support of the second premise, that is

Common sense beliefs have the highest level of initial plausibility.

Mike argues as follows,

“But the nature of common sense beliefs, as such, is that they have the highest initial plausibility of all beliefs. This, in fact, may serve as a useful definition of common sense beliefs; it explains the other features of common sense beliefs that we noted in section II.5. Common sense beliefs are almost universally accepted, regardless of time and place, because they are the most obvious propositions.”  (SVP, p. 33)

    Mike also argues that while massive scientific testimony could convince one that something like the Theorem of Pythagoras was false, it would not convince one, for example, that there were no rocks.

Question:  Is it true that all common sense beliefs have the highest level of initial plausibility?

(1) It is not true that all common sense beliefs have the highest level of initial plausibility, since some common sense beliefs have a higher level of initial plausibility than others.  For example, my common sense belief that I am now having experiences has a higher initial plausibility for me than my common sense belief that I am now seeing a desk.  Moreover, my treating the former belief as initially more plausible than the latter is surely justified, since the truth of the latter belief entails the truth of the former, but not vice versa.

(2) Similarly, the common sense belief that there are other human bodies should have a higher initial plausibility for one than the common sense belief that there are other human bodies that have minds that enjoy experiences. 

(3) Scientific testimony has convinced people that some beliefs that were common sense beliefs – in the ordinary, temporally indexed, sense of “common sense beliefs” – are false.  Thus it was once a common sense belief that a quality with which normal perceivers are directly acquainted – namely, the occurrent, sensible property of redness – was a quality out there on the surfaces of objects such as ripe tomatoes.  If physics is right, there is no reason for believing that there is any such property on the surfaces of ripe tomatoes.

(4) Other common sense beliefs – in the ordinary, temporally-indexed, sense of “common sense beliefs” – that science has given us good reason for abandoning include, for example, the following beliefs:

(a) The belief that when one touches an orange, the matter in one's hand comes in contact with the matter in the orange;

(b) The belief that most of the space occupied by a coin is occupied by matter in the coin, rather than by empty space.

(5) So it can be rational in some cases to abandon common sense beliefs, in the ordinary sense of “common sense beliefs.”  

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6.  In support of the third premise, that is

Philosophical theories do not have the highest level of initial plausibility.

Mike argues that the disagreement over philosophical claims shows that they do not have the highest level of initial plausibility.

Comments

(1) Mike Huemer refers here to philosophical theories.

(2) It is true that philosophical theories do not generally elicit a high level of agreement, and it is fair to say that that shows that philosophical theories do not possess the highest level of initial plausibility.

(3) On the other hand, there can be philosophical claims that do not involve philosophical theories in an ordinary sense, and that may have either very high initial plausibility, or else very high plausibility upon further reflection and argument, so one needs to consider the possibility of a collision between such philosophical claims and common sense beliefs. 

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Mike Huemer advances the following claim: “No skeptic has ever devised an argument whose premises were not more controversial than the common sense beliefs the skeptic seeks to challenge.” (SVP, p. 36)  I shall now argue that this can be done.

3. A First General Point:  Philosophical Theories Versus Philosophical Claims


1. Consider the following claims:

(a) Reality consists of nothing except God plus finite immaterial minds and their mental states.

(b) Berkeley's theory is not significantly more complex than the theory that there are mind-independent external objects.

(c) The observational predictions of Berkeley's theory are the same as the predictions of the theory that there are mind-independent objects.

(d) If two theories S and T generate the same observational predictions, and theory S is only slightly more complex than T, then the ratio of the a priori logical probability of S to that of the a priori logical probability of T will be only slightly different from one.

(e) The a priori logical probability of Berkeley's theory is not significantly lower than the a priori logical probability of the theory that there are mind-independent objects.

(f) Bayes' Theorem is true.  (Or: The definition of conditional probability is consistent.)

Only the first of these would naturally be characterized as a philosophical theory.  At the same time, the other five claims are very relevant to the question of the epistemic status of the first.

2. To see this, let us introduce the following abbreviations:

p = The proposition that there is a specific world, W, involving mind-independent objects.

m = The proposition that there is instead an exactly corresponding Berkeleyan world – that is, a Berkeleyan world in which precisely the same experiences will exist as would exist if p were true.

e = A proposition concerning the totality of the sensory experiences that will exist if p is true.

So e is a proposition that is entailed both by p and by m.

Prob(q) = the a priori logical (or epistemic) probability that q is the case.

Prob(q, r) = the logical (or epistemic) probability that q is the case given that r is the case.

If claims (b), (c), and (d) above are correct, or at least near enough, then it is the case that

(1) If Prob(m)/Prob(p) is less than one, it is only slightly less than one.

But by the definition of conditional probability, which is

Prob(m/e) = Prob(m & e), one has that

Prob(e)

 (2)  Prob(m/e) x Prob(e) = Prob(m & e) = Prob(e/m) x Prob(m)

and, similarly, that

(3)  Prob(p/e) x Prob(e) = Prob(p & e) = Prob(e/p) x Prob(p)

Moreover, in view of the fact that p entails e, we have that

 (4) Prob(e/p) = 1

Similarly, in view of the fact that m also entails e, we also have that

 (5) Prob(e/m) = 1

Substituting 5 and 4 into 2 and 3 then gives us, respectively:

(6) Prob(m/e) x Prob(e) = Prob(m)

and

(7) Prob(p/e) x Prob(e) = Prob(p)

Dividing equation 6 by equation 7 then yields

(8) Prob(m/e)/Prob(p/e) = Prob(m)/Prob(p)

But this means, in view of its being the case that if Prob(m)/Prob(p) is less than one, it is only slightly less than one, that

(9) Prob(m/e)/Prob(p/e) is only slightly less than one.

In short, the a posteriori logical probability that Berkeley's view of reality is correct, relative to the totality of experiences that one has, is either equal to, or else only slightly less than, the a posteriori logical probability that there is a world of mind-independent physical objects.

3. Notice the following important contrast.  If Berkeley's view of the world is true, that is a contingent truth.  In contrast, claims (b) through (f), if true, are necessary truths.

4. This is very important.  For necessary truths can have an initial plausibility that is greater than that of a contingent common sense belief such as that there are rocks.  In addition, even in the case of necessary truths whose initial plausibility is not especially high, investigation can show that the proposition in question is not only extremely plausible, but also more plausible than contingent common sense beliefs concerning the external world.

5. To sum up, then, it is a mistake to think that the only way of challenging a common sense belief is by opposing it by a philosophical theory.  One can instead appeal to philosophical claims that do not involve advancing any philosophical theories, and argue that those claims lead to the conclusion that a certain common sense belief does not have the probability that is being assigned to it.  Moreover, the philosophical claims in question may be necessary truths, and they can have either an initial plausibility that is higher than that of contingent common sense beliefs about the external world, or else a plausibility upon subsequent reflection that is higher than that of contingent common sense beliefs about the external world.

 The way of challenging common sense beliefs that I have just described involves what might be called “purely philosophical arguments.”  But, as we shall see in the next section, there can also be philosophical arguments against common sense beliefs that make use of well-established scientific claims.  One then needs to argue that the scientific claim in question can achieve a level of plausibility that is greater than that of the common sense belief that it is being used against.  I shall not attempt to show that here, but I think that the claim is very plausible.

4. A Second General Point: Inferential Versus Non-Inferential Beliefs


1. The vast majority of common sense beliefs are inferential beliefs.  Thus, for example, in the case of beliefs about presently existing, but not currently perceived objects, all such beliefs rest upon everyday conservation principles.

2. Even if one confines oneself to beliefs about currently perceived objects, those beliefs typically go beyond what one is directly acquainted with, in the following ways:

(a) One believes that the things one sees are not facades.

(b) One believes that the things one sees have insides of a certain sort.

(c) One believes that the things one sees have tactile qualities.

(d) One believes that other observers would also see the things one sees if they were present.

(e) One believes that the things one sees would exist even if one were not seeing them.

3. When beliefs are inferential, the fact that their plausibility is not substantially reduced by certain sorts of challenges is compatible with its being the case that challenges specifically directed against the underlying inferences may radically reduce their plausibility.

4. When a common sense belief is inferential, it is apparent that the plausibility of that belief is a function of the plausibility of the inference involved, and it may then very well be the case that, confronted with a competing inference, leading to an incompatible conclusion, one’s estimate of the plausibility of the original inference – and so also of the original belief – plummets.

5. Suppose, in particular, that the following things turned out to be true:

(a) One's beliefs about external objects that one is currently perceiving are inferential beliefs.

(b) The inference is an inference to the best explanation.

(c) Berkeley's theory does not differ much from the theory of physical objects with regard to simplicity.

Then it would seem that the plausibility of the theory that there is a spacetime world containing mind-independent physical objects should drop very significantly.

5. Some Specific Cases to Consider: Candidate Common Sense Beliefs


If the G. E. Moore/Michael Huemer anti-skepticism argument is sound, then it is always rational, given a conflict between a philosophical theory and a common sense belief, to reject the philosophical theory, rather than the common sense belief.  Is this true?

To see whether this is right, let's consider some beliefs that either are or were common sense beliefs, in the ordinary, temporally indexed sense of that expression, along with some incompatible philosophical theories.

Comments

(1) If one talks, as I just did, about beliefs that either now are or were common sense beliefs, one is operating with a temporally indexed interpretation of the expression “common sense beliefs".

(2) I think that this is our ordinary interpretation of that expression.

(3) If one adopted, instead, Mike's interpretation of that expression, one would need to rephrase things in terms of “beliefs that either are or were candidates for common sense beliefs.”

(4) The issue that arises, in view of the option here, is whether G. E. Moore and/or Mike Huemer have an anti-skepticism argument that applies to common sense beliefs in Mike’s sense of that expression, but not to common sense beliefs in the temporally-indexed sense.

(5) For that to be the case, one would have to be able to show that while beliefs that are common sense beliefs in Mike's sense have the highest initial plausibility at a given time, beliefs that are common sense beliefs only in the temporally-indexed sense at that time do not have the highest initial plausibility at that time.  I do not think that there is any reason for thinking that that is so in general.

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In any case, here are some beliefs that either are, or were, common sense beliefs in the temporally indexed sense of that expression.

(1) The belief that a certain ripe tomato is red, where this is understood as the belief that a young child would have about the color property of the surface of a ripe tomato.

Competing philosophical theory:  Physics is a complete theory of the external world.

(2) The belief that there are mind-independent physical objects.

Competing philosophical theory:  Idealism.

(3) The belief that human behavior is not causally determined.

Competing philosophical theory:  Determinism.

(4) The belief that humans possess libertarian free will

Competing philosophical theories:  (a) Determinism; (b) The view that libertarian free will is incoherent; (c) The view that to the extent that human behavior is not causally determined, what one does is simply a matter of indeterministic quantum processes: there is nothing else that is causally relevant.

(5) The belief that non-human mammals have experiences.

Competing philosophical theory:  Animals have only properties that are reducible to those of physics.  (Compare Descartes.)

(6) The belief that decisions to perform actions are not caused by earlier, purely physical events in the brain.

Competing philosophical theory:  Decisions are caused by earlier, purely physical events in the brain.  (Consider Benjamin Libet's experiment.)

(7) The belief that one's experiences can causally make a difference with regard to the way that one's body moves.

Competing philosophical theory:  Epiphenomenalism.

(8) The belief that there are objective facts concerning the rightness and wrongness of actions, or the goodness and badness of states of affairs, and that we can have knowledge of such objective values.

Competing philosophical theories:  (a) Moral irrealism and (b) Moral skepticism.

With regard to each of the above pairs of a suggested common sense belief, and a competing and incompatible philosophical theory, there are four questions that one needs to ask:

    First, are the theories that I have just characterized as "competing philosophical theories" philosophical theories?

    Secondly, is the belief in question a common sense belief in Mike's sense?

    Thirdly, if it is, is Mike right in holding that it is impossible for there to be an argument that would give us good reason to reject the common sense belief in favor of the competing philosophical theory?

    Fourthly, if the belief in question is not a common sense belief in Mike's sense, was it at one time a common sense belief in the ordinary, temporally-indexed sense of “common sense belief"?

    The point of the fourth question was, in effect, described earlier.  It is that if a belief is a common sense belief in the ordinary, temporally-indexed sense of that expression, but is not a common sense belief in Mike's sense – because, say, it is now widely rejected – then Mike has the task of either (1) showing that the belief in question did not possess, at the relevant time, the same high level of initial plausibility as beliefs that are common sense beliefs in his sense of that expression, or (2) of explaining how people could ever be justified in rejecting the beliefs in question if those beliefs had as high a level of initial plausibility at that time as beliefs that are common sense beliefs in Mike's sense.

As regards the first question, it certainly seems to me that what I have labeled "competing philosophical theories" are indeed such.  Does anyone think that in some of the above cases this is not so?

The other questions call for more discussion, so let's consider each candidate in turn.

Candidate 1:  Colors, as a child would understand them, are real, and are properties of the surfaces of objects.

Competing philosophical theory:  Physics is a complete theory of the external world.

1.  What are young children saying when they say that a tomato is red? One thing that they are clearly not saying is this:

(1) “Ripe tomatoes have the power to absorb the following wavelengths of light . . . and the power to reflect the following wavelengths of light . . .”

But it also seems clear that they are also not saying this:

(2) “Ripe tomatoes have the power to produce experiences in normal observers under normal conditions that have the property of qualitative redness.”

For while it may be argued that arriving at the belief that is expressed by sentence (2) does not, in contrast to what is so in the case of sentence (1), require specialized scientific knowledge, the belief in question is not the belief that people naturally acquire.  The belief that people naturally acquire involves the concept of a sensible property of redness – where by this I mean the property that Mary in Frank Jackson's “knowledge argument” is aware of when she learns what redness is.  When a child says that a tomato is red, it is this sensible, non-dispositional property that is being attributed to the surface of the tomato.  Redness is a property with which a child is directly acquainted, and in such a way that the child, like Mary, knows what redness is.  It is not, as David Armstrong, for example, contends, some property about whose intrinsic nature one initially knows nothing.

In short, there is a certain property with which a child is directly acquainted – the property of redness – and a child, in believing that a ripe tomato is red, believes that that the surface of the tomato has that property.

Is this a common sense belief?  One might object that it is not, on the grounds that one does not now have to be a philosopher or a madman to reject it.  But this defense seems unsound to me.  For suppose that one goes back a few hundred years, and ignores certain parts of Asia.  It would surely have been reasonable then to have viewed the belief in question as a common sense belief in the temporally indexed sense of that expression.  But would it not also be true, at that time, that that belief would have had just as high a level of initial plausibility as beliefs that Mike would view as common sense beliefs – such as the belief that other humans have minds?  But if that is right, then, if Mike Huemer's argument were sound, it would have been reasonable at that time to continue to accept that common sense belief when it came into conflict with a philosophical argument, as it did.  But, in fact, those who are familiar with the relevant scientific information have almost universally come to hold that ripe tomatoes do not have the sensible, non-dispositional property of redness.

The upshot is that the belief that things are colored in the relevant sense was once a common sense belief, but it has been abandoned by almost everyone who is familiar with the relevant scientific facts.  So some common sense beliefs ¬ in the ordinary sense of “common sense belief” – have succumbed to philosophical arguments based on well-established scientific premises.

Candidate 2:  There are mind-independent physical objects.

Competing philosophical theory:  Idealism.

Is this a common sense belief, in Mike's sense?  My argument for the claim that, contrary to Mike's view, it is not, is as follows:

(1) Hinduism, which is the religion of over 600 million people, involves the idea of maya, where this is the view that there is no physical world, that what one has is, instead, an illusion.

(2) A significant number of Hindus affirm this belief, and there is nothing in their behavior that provides a reason for thinking that they are wrong in this self-attribution.

(3) These people are not all either philosophers or mad.

(4) Accordingly, the belief that there are mind-independent physical objects is not a common sense belief in Mike's sense.

Mike's response to this argument was that he found it hard to believe that people really believed the doctrine of maya.  His ground, I think, involved the claims, first, that Hindus do not act in the way that they would if they believed that the physical world is an illusion, and, secondly, that the way that one acts can show that one is mistaken in attributing a certain belief to oneself.

But if that is Mike's ground, the objection is that a Berkeleian does not, on the whole, have reasons for acting differently than a person who believes in a physical world.  So, for example, if Berkeley is right about the nature of reality, and one has the experience as of putting one's hand in a fire, one's pain will be just as great as it would be if there were a physical world.

Consequently, I don't think that there is any very good ground for being skeptical about the correctness of a Hindu who claims to believe that the physical world is an illusion.

Now it is true, it seems to me, and as Thomas Reid pointed out, that if Berkeley's theory is true, then one does not have a good reason for believing in the existence of other human minds.  But given that very few people – including Berkeley – have noticed this fact about Berkeley's theory, I do not think that this fact is good grounds for concluding that Hindus do not have the belief that they take themselves to have – that is, the belief that the physical world is an illusion.

In addition, however, compare the following beliefs:

(a) There is a perfectly loving, all powerful, and all knowing being who created and who rules over our world.

(b) There is some being who has produced a grand illusion that people experience, to the effect that there is a physical world.

The first of these propositions seems to me much more likely to be false, given the immense suffering that both innocent persons – including children – and animals undergo, than the second.  But the first proposition is nevertheless affirmed by an extremely large number of people.  So why should one accept Mike's view that Hindus do not really accept the second belief?

Furthermore, religious beliefs often come as a package deal, with the result that people accept beliefs that are immensely implausible  – such as the belief that the earth is only a few thousand years old, which is still accepted by more than 40% of our fellow Americans – because they view those beliefs as an essential part of a total view of the world that they find appealing.  So even if it were true that there would be no grounds for behaving as one does if one believed that the physical world was not real, that would not provide a good reason for concluding that Hindus do accept the doctrine of maya.

Finally, there is a type of experience that is found in all, or virtually all, cultures – what are known as introvertive mystical experiences.  Moreover, in the description of such experiences that is, arguably, most free of the importation of prior beliefs – namely, the monistic account offered in Eastern religions, as contrasted with the monotheistic account offered by Christian mystics – a central aspect of the experience is the sense that the world of space and time is not real.  The Hindu doctrine of maya is largely based, I believe, on such introvertive mystical experiences.

The second issue is this.  If, contrary to what I have just argued, the belief that there is a world of mind-independent physical objects were a common sense belief in Mike's sense, could it be defended against skeptical challenges by Mike's argument?

Mike's argument appeals to the idea that common sense beliefs are characterized by the "highest level of initial plausibility".   But judgments of plausibility are judgments of probability.  How reliable are ordinary judgments of probability?

Some judgments of probability are based upon observations of relative frequencies, and such judgments may be relatively sound.  But in the present case, there is no information about relative frequencies that bears upon the issue.  So what we are being asked by Mike to do is to view, as very reliable, judgments of probability, first of all, that are not based upon relative frequencies; secondly, that are being made by people without serious consideration of competing hypotheses – such as the mystically-based doctrine of maya; and, thirdly, that are judgments that Mike himself is unable to support by appealing to principles of probability or inductive logic.  

Candidate 3:  The belief that human behavior is not causally determined.

Competing philosophical theory:  Determinism.

Is the belief that human behavior is not causally determined a common sense belief?  I think that it is, since I think that it is natural to think that, at any given time, one could, for example, either move one's hand to the right, or move it to the left.  Moreover, one does not, initially, seem to have any reason at all for thinking that, on the contrary, what one does is in fact causally determined.

Is it then true that science could no more convince one that this belief was false than it could convince one that there were no rocks?

This does not seem right.  For couldn't it have been the case that the correct theory of physics was Newtonian, and so deterministic?  ?  Or mightn't the indeterministic interpretation of quantum physics that is presently accepted by most physicists come to be replaced by the deterministic alternative?  Or mightn't present, indeterministic theories in quantum mechanics be replaced at some point by a deterministic theory?

It might be objected that what physicists would have shown, in such cases, would be only that determinism held with regard to inanimate objects.  But couldn't the work of physicists be supplemented by neurophysiological experiments that established that events taking in place in the brain conformed to the deterministic laws discovered by physicists?  If so, then this third belief would be shown to be false.

Candidate 4: The belief that humans possess libertarian free will

Competing philosophical theories:  (a) Determinism; (b) The idea of libertarian free will is incoherent; (c) The view that to the extent that human behavior is not causally determined, what one does is simply a matter of indeterministic quantum processes: there is nothing else that is causally relevant.

Is the belief that humans possess libertarian free will a common sense belief?  I think that it is, since it seems to me, as was mentioned in connection with the previous candidate for a common sense belief – namely, that human behavior is not causally determined – that it is natural to think that, at any given time, one could, for example, either move one's hand to the right, or move it to the left, and that, moreover, in thinking that one can do either of those things, one is thinking that one has some sort of power to do either of those things, a power that is “under one's control.”

It might well be objected, however, that if the claim that is advanced the second of the two competing philosophical theories just mentioned – namely, the claim that the idea of libertarian free will is incoherent – is true, then there is no belief here to be a common sense belief.

I'm inclined to think, however, that one can respond as follows.  First of all, the idea of libertarian free will can be characterized in a relational, or functional way: libertarian free will is something whose possession entails that one's actions are not causally determined, and whose possession is also sufficient to make it the case that one is causally responsible for one's actions.  The claim that libertarian free will is incoherent is then not the claim that that functional or relational concept is incoherent, but, rather, the claim that there is no coherent, intrinsically characterized power or property answering to that relational or functional description.

Could this belief be overthrown?  Since having libertarian free will is incompatible with its being the case that one's behavior is causally determined, if the belief that one's behavior is not causally determined could be overthrown, then so could the belief that one has libertarian free will.

Candidate 5: The belief that non-human mammals have experiences.

Competing philosophical theory:  Animals have only purely physical properties. 

Is it a common sense belief that cats and dogs, for example, have experiences?  It would certainly seem that it is.

Is it true, then, that a philosophical argument based on scientific findings could not give one good reason for abandoning this belief in favor of the Cartesian belief that non-human animals are physical automata without experiences?  It seems to me that it is not.  For imagine that, in the case of human beings, neurophysiological investigations locate a "visual experience module" such that, when this is damaged, the human in question, while having a dramatic type of blindsight, reports having no visual experiences at all.  Suppose that comparable modules are found for all of the other senses.  Suppose, finally, that nothing in the brains of non-human mammals corresponds to this part of the human brain, and that all of the structures in all parts of the brains of non-human animals correspond to structures in human brains that are not sufficient for the having of experiences.  Would not information along these lines make it reasonable to conclude that while non-human animals behave as if they had conscious experiences, in fact consciousness only emerges with the development of certain neuronal structures that are only present in the human brain, so that Descartes was right, and non-human mammals do not have experiences of any kind? 

Candidate 6:  The belief that decisions to perform actions are not caused by earlier, purely physical events in the brain.

Competing philosophical theory:  Decisions to act are caused by earlier, purely physical events in the brain.

Is this a common sense belief?  Again, I think that it is.  One is aware of conscious processes of considering alternative actions, and the pros and cons of each.  Then, at a certain point, there is a conscious experience of making a decision, and it seems very natural to think of that occurrence as one that is not caused by some earlier, purely physical event.

Some scientists have reported, however, that there are brain events that take place a very short time before the conscious experience of making a decision – events that they think it reasonable to view as causally giving rise to the conscious experience.  Thus Benjamin Libet, in a famous article entitled “Do We Have Free Will?” that was published in the Journal of Consciousness Studies, 6, No. 8–9, 1999, pp. 47–57, says,

“I have taken an experimental approach to this question. Freely voluntary acts are preceded by a specific electrical change in the brain (the ‘readiness potential', RP) that begins 550 ms before the act. Human subjects became aware of intention to act 350–400 ms after RP starts, but 200 ms before the motor act. The volitional process is therefore initiated unconsciously.”

 The upshot then, as Michael S. Gazzaniga describes it in chapter 3 of his book The Mind's Past – entitled "The Brain Knows Before You Do" – is that “. . . before you are aware that you're thinking about moving your arm, your brain is at work preparing to make that movement."  (  The Mind's Past, (Berkeley and Los Angeles: The University of California Press, 1998), page 73)

But if this is right, is this not a good reason to abandon the common sense belief in favor of the competing philosophical theory that events that involve the consciousness of coming to a decision are caused by earlier, purely physical events?   

Candidate 7:  The belief that one’s experiences can causally make a difference with regard to the way that one's body moves.

Competing philosophical theory:  Epiphenomalism.

Is this a common sense belief?  It certainly seems to me that it is.  When, for example, one tastes something, and one is asked how it tastes, surely it is extremely natural to think that the quality of the experience that one is having plays an essential causal role in determining the words that one utters in answering the question of how the thing tastes.

Is it true, then, that an argument for the competing philosophical theory of epiphenomenalism could not prevail against this common sense belief?  Again, this does not seem right.  As with the case of Candidate 3 above, it would seem that, on the one hand, physicists could show that determinism held with regard to inanimate objects, and then cognitive scientists could establish, via extensive neurophysiological experiments, that events taking in place in the brain were not exceptions to the deterministic laws discovered by physicists.  If this is so, then the common sense belief that experiences can make a difference with respect to how humans behave could be shown to be false.

Candidate 8:  The belief that there are objective facts concerning the rightness and wrongness of actions, or concerning the goodness and badness of states of affairs, and that we can have knowledge of such objective values.

Competing philosophical theories:  (a) Moral irrealism and (b) Moral skepticism.

Is this a common sense belief?  Again, it seems to me very plausible that it is.  For one thing, have anthropologists ever found a society where people did not have beliefs about the rightness and wrongness of actions?  For another, though many people question the existence of objective values, it is generally the case that when certain issues arise, they do not treat those who disagree with them as simply having different preferences that are no more problematic than their own.  A person who liked to relax by torturing animals would not generally be viewed as simply having unusual tastes.

Is it true that this common sense belief is secure, and should prevail in the face of any challenge from moral irrealism or moral skepticism?  Again, this does not seem to me true.  Consider, for example, the argument from the cultural relativity of values against the view that there are objective values.  The normal response to this argument is to draw a distinction between basic moral principles and derived ones, and to argue that the moral disagreements that one finds between different societies are, on the whole, disagreements about derived moral principles.  This response, however, is by no means unproblematic, since there seem to be a number of cases where there is disagreement concerning principles that, at least for some people, appear to be basic moral principles, sometimes involving very firm intuitions on both sides.  Here are a few examples:

(1) The enjoyment of sexual pleasure is only morally permissible within marriage, and when the sexual activity in question is one that is open to the possibility of conception.

(2) The direct killing of any innocent human being, regardless of his or her condition, and regardless of whether he or she asks to be killed, is always seriously wrong.

(3) There are some actions that should never be performed, regardless of the consequences of not performing the action.

(4) The killing of potential persons is morally on a par with the killing of persons.

(5) Killing and letting die are morally on a par.

(6) Suicide is morally wrong, even in cases where one is terminally ill and suffering terribly.

(7) The use of mind-altering drugs is morally wrong.

(8) People who have intentionally killed others when it was wrong to do so should be executed.

(9) We have no obligations with regard to future generations.

(10) Affluent countries have no obligations with regard to people starving to death in other countries.

(11) To each according to his needs.

(12) Goods should be distributed in accordance with desert.

(13) The world is a better world if good and evils are distributed in accordance with desert.

(14) All rights are only negative rights, such a right not to be killed.  There are no positive rights, such as a right to be saved from death.

(15) If two worlds have the same quantity of goods, but the goods are differently distributed, the world with the more equal distribution is the better world, other things being equal.

(16) A world where John suffers on a particular occasion, and is comforted by someone, is a better world than one where John does not suffer on the occasion in question. 

These disagreements, all of which I think are most likely to be, or to be very closely related to, disagreements about basic moral principles – that is, disagreements about rightmaking and wrongmaking, or goodmaking and badmaking properties – are disagreements about extremely important issues.  Would one expect such disagreements if there were objective values to which people had cognitive access?  Wouldn't one rather expect that the level of disagreement would be more on a par with what there is, say, in the case of the colors, or shapes, of objects?

It seems to me, then, that the argument from relativity poses a strong prima facie challenge to the claim that there are objective moral values to which humans have cognitive access.

There are, in addition, other challenges.  One is that it seems clear that the inculcation of moral values by parents in their children can produce extremely firm moral opinions and associated moral feelings, such as guilt and shame that seem unrelated to the truth or falsity of the belief in question.  Consider, for example, the Biblical views, found in the Old Testament, that women who are not virgins when they are married should be stoned to death, or that homosexuals should be put to death, or that people who have sex with animals should be executed, or that rebellious sons should be killed.  If there are objective values, these particular moral beliefs are, I would hope, false.  But when people who have such beliefs introspect, carefully and conscientiously, are they able to detect any difference between those moral beliefs and others that, if there are moral values, one would hope are true – such as that killing innocent people is prima facie seriously wrong?

One might compare, here, the case of arithmetic.  Imagine parents who inculcate in their children the belief that Fermat's Last Theorem is true.  Would such children claim to be able to 'see' that Fermat's Last Theorem is true in just the way that they can see, for example, that 2 + 2 = 4?  Isn't there something phenomenologically special about one's recognition of simple mathematical truths?

In short, it seems to me that it is not at all clear that the common sense belief that there are objective values to which one has cognitive access will not, in the end, turn out to be such as should be abandoned in the face of relevant philosophical arguments. 

6. Concluding Comments on the G. E. Moore/Mike Huemer Argument


 (1) It is not true, as Mike Huemer claims, that in a conflict between common sense views and philosophical theories, common sense views should always prevail on the grounds that common sense views "have the highest level of initial plausibility", while competing philosophical theories do not.

(2) One reason is related to Bertrand Russell's remark, which he made with regard to color and the manifest image version of naïve realism, to the effect that the manifest image version of naïve realism leads to the belief that physics is true, which in turn leads to the conclusion that the manifest image version of naïve realism is false.  The point, then, is simply that some common sense beliefs involve observations that serve to support scientific theories that, in the end, are ultimately very firmly established indeed, and where some of those scientific theories can then be used by philosophers to argue that other common sense views are false. 

(3) The picture that emerges is that even if common sense views are often both natural and reasonable initially, they are typically based upon a very limited range of considerations.  Much broader considerations, often involving much deeper observations, are often evidentially relevant to common sense beliefs, and, because of this, philosophical theories that appeal to such considerations can perfectly well turn out to be more reasonable than the relevant common sense beliefs with which they conflict.

(4) Finally, there is another way in which one could in principle show that a common sense belief is not justified, and that does not involve an appeal to any scientifically established beliefs.  It is that one might be able to use a priori principles of logical probability to show that a particular common sense belief was not likely to be true, and therefore not justified.

(5) The clearest illustration of this possibility arises in connection with skepticism about induction.  Thus, consider the following argument for skepticism concerning non-probabilistic laws of nature:

Laplace's Rule of Succession

If only two outcomes are possible when an event of type E occurs, and one of those two possible outcomes – say, the occurrence of an event of type F – has occurred n times, the probability that an event of type F will occur the next time an event of type E occurs is equal to  (n + 1)/(n + 2).

As can be shown, it then follows that if only two outcomes are possible when an event of type E occurs, and one of those two possible outcomes – the occurrence of an event of type F  – has occurred n times, the probability that an event of type F will occur the next m times an event of type E occurs is equal to  (n+ 1)/(n + m + 1)

Suppose, then, that there is reason to believe that in the history of the universe, an event of type E will occur an infinite number of times.  The probability that an event of type F will occur every time is equal to the limit of   as m goes to infinity, which is zero.

Apparent Conclusion

    It is impossible to establish that a non-probabilistic law of nature obtains, since no matter how many times events of type E have been followed by events of type F, the probability that that will always be so is zero (or, if one accepts infinitesimals, infinitesimally close to zero).

(6) Finally, in the case of skepticism concerning the existence of a mind-independent, physical world, there is the type of argument that I mentioned earlier:

(a) The idea of there being logical probabilities is a sound one, and so there are numbers that are the a priori logical probabilities of the Berkeleian hypothesis, and of the mind-independent world hypothesis.

(b) The extensive isomorphisms between these two hypotheses, and the fact that the Berkeleian hypothesis is not significantly more complex than the mind-independent world hypothesis makes it likely that the former hypothesis does not have a significantly smaller a priori logical probability than the latter.

(c) These two metaphysical theories make the same predications with regard to all experiences that humans will have.

(d) In view of (c), the logical probability of the occurrence of any experience, E, should not be any different on Berkeley's hypothesis from what it is on the mind-independent, physical world hypothesis.

(e) In view of (b) and (d), it follows from Bayes Theorem that the a posteriori probability of the Berkeleian hypothesis will not be significantly smaller than the a posteriori probability of the mind-independent world hypothesis.

(f) Given that this is so, one cannot be justified in assigning a probability to the mind-independent world hypothesis that is significantly greater than one half – let alone greater than, say, 0.99.

Concluding Comments


(1) Why do I say “apparent conclusion” above, given that the conclusion certainly follows from Laplace's Rule of Succession?  The reason is that Laplace's Rule of Succession rests upon unsound equiprobability assumptions – albeit ones accepted by Laplace, by Thomas Bayes, and by Rudolf Carnap – and when those unsound equiprobability assumptions are replaced by sound ones, the conclusion in question no longer follows.

(2) So the above argument for (partial) inductive skepticism is unsound.

(3) The same is true of the above argument for skepticism concerning the existence of a mind-independent, physical world.  The error, I would argue, is that it is not true that the a priori logical probabilities of the Berkeleian hypothesis, and of the mind-independent world hypothesis, are roughly comparable: the a priori logical probability of the Berkeleian hypothesis is, it turns out, much lower than the a priori logical probability of the mind-independent world hypothesis.

(4) The overall conclusion is that the way to refute skepticism is not by anything like a G. E. Moore Shift type of argument. What one must do is to bring the idea of logical probability to bear upon the issue, and to show that the a priori probability of the skeptical hypothesis that one is considering is much lower than the a priori probability of the non-skeptical alternative.

3. Stroud's Defense


    In this section, Mike Huemer considers an objection to the G. E. Moore Shift Argument advanced by Barry Stroud. Mikes basic line of argument involves, as I see it, supplementing the line of argument that he set out earlier with the claim that there are epistemological views that are alternatives to skepticism that enable one to preserve one's common sense beliefs.

    The relation between what Mike is arguing in this section and the argument that he set out earlier, on page 36, is not as clear as it might be. One way of viewing it is as follows.  Someone might claim that the skeptic's epistemological principles can be seen, upon reflection, to be necessary truths. (It is not clear whether Barry Stroud is claiming this or not.) But if they are necessary truths, then they can have a higher level of plausibility – not necessarily initial plausibility, but plausibility upon reflection – than common sense beliefs. The idea is then that initial plausibility does not carry the day, since if reflection leads to any change in plausibility, it is the resulting plausibilities that are relevant.

    If this is right, then what Huemer is doing is arguing that reflection upon the skeptic's epistemological principles does not lead to the conclusion that they have a resulting probability that is greater than that of common sense beliefs, and that it does not do so because there are alternative epistemological principle that are not clearly mistaken.

    Here is the concluding paragraph of Mike Huemer's discussion in this section:

    “ I think that Stroud would accept that, when such a theory is put forward, it becomes the basis of a legitimate objection to the skeptic––indeed, Stroud's major complaint against Moore seems to be that Moore has declined to do any such thing; Moore has nothing more to say than that skepticism is wrong because he, Moore, knows “this is a pencil.”  The very point I want to make here is that the Moorean argument, or something very much like it, can supplement and strengthen the presentation of an alternative, nonskeptical theory of knowledge.  Once we have two alternative, initially plausible epistemological theories before us, if one of them is consistent with our everyday, prephilosophical beliefs about what people know, while the other is radically revisionary, this fact becomes a strong argument in favor of the former.  In the following chapters of this book, I present precisely such a theory––a theory that maintains our common sense beliefs about perception, knowledge, and justification to a greater extent even than most nonskeptical philosophers would think possible.”                                  (SVP, p. 44)

Comments

1.  My view is that the fact that something is a pre-philosophical belief does not ultimately have any epistemological weight.  One has to investigate whether the pre-philosophical belief is justified or not.

2. The key to such an investigation, moreover, is bringing the concept of logical probability to bear upon the question – unless the belief is one that is justified via direct acquaintance with a state of affairs that is a truthmaker for the proposition in question.