Some doubts about skepticism

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  • SOME DOUBTS ABOUT SKEPTICISM

    L. RESNICK

    This is a strategy paper done in broad strokes. The first part tries to lay out the basic strategy of philosophical skepticism. The second part traces out the consequences of following that strategy. And the third part is a discussion of some strategies which may be used against skepticism.

    It is a remarkable feature of skepticism that whereas almost no one believes the skeptic's conclusions, nearly everyone takes the skeptic's arguments seriously. Why is this presumably false theory so significant? One fundamental reason is that a skeptic, in effect, claims to be more intellectually scrupulous than the rest of us, and intellectual scrupulousness is to lovers of knowledge as piousness is to lovers of the Divinity. More is better. There is no such thing as too much.

    The skeptic's modus operandi is to uncover possibly false presuppositions of some of our most fundamental beliefs, to show that there is no satisfactory independent means for proving that the presupposition is true, and to construe the presupposition as a premise in an argument which has the fundamental belief as a conclusion. Then, using the plausible dictum that a chain of reasoning is only as strong as its weakest link, the skeptic strikes home with his conclusion that we are not justified in claiming to know that the fundamental belief is true.

    For example, my belief in the existence of the physical world is dependent on the evidence of my senses. But my senses either are a reliable guide to what is really there or they are not. There is not available to me any independent means of establishing that they are reliable fo r I cannot perceive physical reality independently of my sense experiences and verify that what they tell me is a close match to what is really there. Thus, although the reliability-of-the-senses

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    premise is apparently essential to the inference that there is a physical world, it cannot be verified or even supported by any evidence available to me. Thus, I have no way of knowing whether or not there really is a physical world.

    Analogously, my belief that other people have inner states similar in kind to mine is based on the fundamental assumption that our observable "outer" similarities are matched by unobservable "inner" similarities, so that if my body and my behaviour closely resemble the bodies and the behaviour of others then my inner states are of the same sort as their inner states. Since there is no way for me to observe the inner states, if any, of others I have no way to confirm this fundamental assumption. Thus, even assuming that there are others, there is no way for me to know whether or not they have inner states similar to mine.

    Let me give one more example, lesser known, but perhaps my favourite skeptical argument. It comes from W.T. Stace's paper, "The Refutation of Realism. ''1 Assuming, Stace says, that our sense experiences are veridical, that is, that the entities we perceive are there in reality, no one knows whether or not any entity exists unperceived Consider the case of two exactly similar fires set in the same ftteplace on succeeding days. In both cases we observe the stacking and lighting of the wood; in both cases we observe after several hours the ashes, a few glowing embers, the warm hearth, the acrid smell and a higher temperature in the room. The difference is that, in the case of the first fire, we stayed in the room during its entire course, but in the case of the second fire, no one observed it between the time it was started and the point, several hours later, when observers returned to f'md the ashes, embers, warm hearth, acrid smell and elevated room temperature. Dogmatists will want to conclude that during the time it was unobserved, the unobserved fire went through the same causal sequence which, in the observed fire, produced the observed results. An utterly unfounded conclusion, says Stace, because it assumes that causal sequences of natural events are the same whether observed or not. Where is the warrant for this fundamental assumption? Never once in the history of the universe has anyone had the slightest evidence that observed causal sequences and unobserved causal sequences are the same. This is owing to the fact that it is quite impossible to observe even a single instance of an unobserved causal sequence to verify that it is the same as an observed causal sequence. In the complete absence of any relevant evidence whatever, the leap to the conclusion that unobserved causal sequences are the same as observed ones is an absolute shocker.

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    II

    I want to establish first that if one is committed to this extreme level of intellectual scrupulousness then one must hold that nothing can be known. Take a simple logical inference: P.Q/:.P. Are there any possibly false presuppositions here? Well surely there is the possibly false presupposition that "P.Q" is wetl-formed and that "P" and "Q" are propositional variables. What evidence do I have that this presupposition is true? If I don't know whether other people have minds, it's hard to see how their assurances about "P" and "Q" carry any weight at all, but worse, since I don't know whether there are any other people or any physical objects including logic texts, etc., it is hard to see that I have anything to go on but my recollection or my present feeling of conviction that "P" and "Q" are propositional variables. The latter is too notoriously subject to error to merit further consideration: the road to ignorance is paved with unshakable convictions. And as to recollection: memories either are or are not a reliable guide to the past, but I have no means for deciding the matter since I have no direct access to the past. So it is clear that my belief that I know what "P.Q" means rests on assumptions which I cannot justify. Thus, I don't know what "P.Q" means and a fortiori, t do not know whether or not P follows from P.Q. But wait! Isn't there a way of salvaging some knowledge? I've just conceded that I don't know that P follows from P.Q because I don't know that "P" and "Q" are propositional variables or that "P.Q" is well-formed, or, one could add, that "dot" is a constant for "conjoined with." But in that case don't I know the conditional that i f "P" and "Q" are propositional variables and "dot" is a constant for "conjoined with", then P follows from P.Q? Only if my convictions about the meanings of "propositional variable", "conjoin" and "follows from" are correct. Let me condense a long line of reasoning into a simple point. Whenever I make assertions, entertain questions or even just think about abstract notions, I use language. There is no way for me to prove, by skeptic's standards, that I am using the language correctly. But unless I know that I am using the language correctly I do not know whether what I think by means of language is correct. In order to have any grounds for believing that I am using language correctly, I would need to have some grounds for believing that my convictions and memories about the meaning of words are (at the very least) more often correct than incorrect. This in turn requires some method independent of my convictions and

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    memories for determining what the actual meanings are; direct access to meaning. But there is no such thing, short of wandering disembodied among the Forms. Assuming that Plato was wrong about that possibility it follows that I am never justified in making any assertion at all. If I have no method whatever for determining what "P" means, then of course I have no idea whether it is meaningful at all. Any purported use of language may be an actual case of gibberish. So it is not merely that "I know that P" is always false, but for any alleged assertion "P" I haven't adequate grounds for believing that it is an assertion at all, much less that it is a true assertion.

    I began this section by saying I wanted to show that commitment to skeptic's scruples leads to the view that nothing can be known. But of course only the most unsophisticated skeptics would claim that it can be known that nothing can be known. In any case, the consequence of extreme intellectual scrupulousness is much more anarchic: it is that one cannot have adequate grounds for believing that P, or that not P, or that either P or not P. In each case there are possibly false presuppositions about the meanings of the terms, about what counts as grounds or about whether these are so much as well-formed formulas. Thus I should not have said, in the previous paragraph, that "I know that P" is always false, but rather that nothing epistemically relevant can be determined about it at all. Nor does it afford the slightest comfort or aid to switch to talking about concepts rather than words or language. It is no less possible to fail to grasp a concept than it is to fail to use a term correctly. Whenever I use any concept, C, it is possible that I have it wrong, and I have only my recollection, my convictions and the apparent understanding of others and perhaps a few more equally weak reeds to grasp at. This is not the stuff of which satisfied intellectual scruples are composed.

    In short it seems to me that the consequence of the skeptic's scruples is to be reduced to silence appropriate to that of which, so far as one can know or have adequate grounds to believe, nothing intelligible can be said.

    Ill

    If I have got the consequences right does this constitute a refutation of skepticism? There is a certain plausibility in claiming that by modus tolens, since the consequences are absurd, the

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    antecedent conditions laid down by the skeptic must be rejected. But if the severe requirements of the skeptic are to be rejected, we need a substitute.

    I take it that most of us would prefer to reject the foundationalism which started us off on the frictionless slope. A popular alternative is to take our fundamental beliefs to be adequately justified if the supposition that they are true is part of our best explanation of the phenomena we observe. "Physical object" and "other minds" designate theoretical constructs in our best theory and therefore, although there is no independent verification that such entities exist, independent verification is unnecessary. Truth and knowledge are essentially notions which arise from coherence, rather than from correspondence with an independent reality.

    This coherence model of justification is certainly attractive, especially considering the drastic consequences of the other alterna- tive. Nevertheless, I don't like it. I don't wish to deny that it gives us a useful way of accounting for our belief in quarks and mesons but I have grave doubts that it can be used to justify our basic beliefs in the existence of the physical world or in the reality of the past or in the existence of other minds. In the case of quarks and mesons we can review the inferences which led to the postulates and we can survey the range of alternative theories and draw conclusions about whether the generally accepted explanation is the best one. These are in most respects open conclusions openly arrived at. But it is very different with the postulate that there is an external world. Does anyone seriously suppose that there was a time, long ago, when humans had not developed the theory that there is an external world, a time during which rival theories vied for support and in which some of the most interesting debates in history would have taken place in a long lost "neutral" language - a time during which isolated primitive tribes held out for solipsism or formed alliances with Parmenadean forces to resist Naive Realism? Surely not. The alternative which one is forced to is that the theory construction which results in the development of the construct "physical world" takes place in the preconscious mind (or in the developing brain) of each normal human being. The part of this picture which I find right is that it is a normal part of one's development to come to believe that there is a physical world, that there are other minds, that most causal processes are unaffected by being observed, etc. These are just as natural, in my view, as constancy phenomena, in which distant objects which occupy a small part of one's visual field are

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    nevertheless perceived to be very large objects which do not cl~ange in size even though, as one comes closer, they occupy a much larger part of one's visual field.

    The part of the picture of pre-conscious theory construction which I don't f'md plausible is that it should be thought of as providing a }ustification of our belief in the physical world. If we are, in effect, programmed to hold a certain view then how can we also be in a position to assess the truth of the matter? Consider two different possibilities. First, that I am not programmed to believe in the physical world, I merely reason to that belief. Second, that I am programmed to believe that there is a physical world. If the second case obtains then, as I have just implied, there doesn't seem to be any way for me to assess the correctness of my belief. Suppose that first alternative is the case. Well, inferences are either sound or not sound and in order to tell one must examine the premises and the conclusion which is alleged to be derived from them. In the absence of these data there is no way to judge the inference. And I submit, if there are such inferences in my preconscious, I certainly am unable to bring their premises into my conscious mind. Furthermore, what would the premises be like? "I am having a visual sensation of a table. I am having a tactual sensation of a table. Ergo, there must be a table"? Put this way the premises sound question-begging. Is there a neutral language, a language not containing implicit physical world postulates which I used to describe the experiences I was having before I invented the hypothesis about the physical world? Perhaps there is such a language. I doubt it, but even if there is, until we can understand it and reconstruct the reasoning which led to the view that the explanation containing physical world postulates is better than any other explanation, we are in no position to assert that the inference is sound nor that of all available alternative hypotheses, the "physical world" hypothesis is the best or most coherent.

    In Thought Harman says that we should turn skepticism on its head. You are to use the fact that you accept the hypothesis as a sign that the hypothesis is simpler and more plausible than alternatives. The fact that you accept a hypothesis about other minds, as opposed to the inverted spectrum hypothesis shows that the usual hypothesis is simpler, less ad hoc and more plausible...

    Similarly with the knowledge of the external world. That you accept the hypothesis of the external world shows that it is reasonable...

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