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Januar 2005

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Theories of Knowledge

Is a naturalised epistemology bound to leave unanswered some important epistemological questions?

Lukas Graf

For Quine epistemology as it is traditionally approached in philosophy is mistaken because it is based on the untenable concept of foundationalism. However, Quine’s contribution to epistemology is not merely a destructive one; he comes up with a new theory. Anyone assessing this theory, naturalised epistemology, ultimately wants to know whether it provides an answer to the central questions of epistemology. In this paper it is dis­cussed whether naturalised epistemology is bound to leave some of these questions unanswered.

The essay starts with a definition of naturalised epistemology, followed by an explanation of the relevant epistemological questions. Then the two key questions in this context, the first relating to the existence of the external world and to scepticism and the second to the justification of beliefs, are examined more closely.

Central to naturalised epistemology is the claim that epistemology is a branch of psychology. ‘The stimulation of his sensory receptors is all the evidence anybody has had to go on, ultimately, in arriving at his picture of the world’¹ and it is psychology which studies how humans construct their beliefs about the world given the sensory stimuli they receive. In the same way, the ‘new’ epistemologist seeks to explain how theoretical output is caused by sensory input; he studies the causal relationship between meagre input and torrential output. That is to say, epistemology is conducted in a scientific manner, and hence naturalised.

In Quine’s opinion epistemology is a discipline of science, where science can be said to be the more successful enterprise than philosophy, exemplified by the phenomenon that, with developments in traditional epistemology, things are becoming more rather than less complicated. In the new setting philosophy and science differ only in degree, not in kind. Foundationalism is replaced by naturalised epistemology and the foundational approach to epistemology merges into a scientific one.² Quine brings out the difference between naturalised and traditional episte­mology in the following way:

‘The old epistemology aspired to contain, in a sense, natural science; it would construct it somehow from sense data. Epistemology in its new setting, conversely, is contained in natural science, as a chapter of psychology.’³

Hence, it can be said that traditional epistemology is pursued a priori whereas naturalised epistemology utilizes empirical investigation. How­ever, if there is an area of epistemological investigation which can only be approached a priori, then naturalised epistemology is unable to answer some important epistemological questions:

‘If the opponents of naturalism are correct, then there are legitimate episte­mological questions which are susceptible to a priori investigation; these questions, they would argue, are rightly regarded as purely philosophical.’⁴

On the assumption that the questions that a traditional epistemologist asks are vital to any theory of knowledge, it follows that an important epistemological question which naturalised epistemology is bound to leave unanswered is a question that is important to the traditional epistemolo­gist but cannot be answered by a naturalist in epistemology.

An epistemological question to be considered in this connection is a question that relates to scepticism and the existence of the external world. Traditional epistemology is concerned with scepticism and asks whether there is an external world and what it is like.

In attempting to answer this question the traditional epistemologist is not making use of any scientific findings. Conversely, Quine’s claim that epistemology is contained in natural science implies that naturalised epistemology does make use of scientific findings.

For a traditional epistemologist the existence of the resources of science is questioned in exactly the same way as everything else and, hence, he does not allow for a presupposition of the existence of the resources of science in order to use them as evidence for other things. Quine puts it in the following way: ‘The old tendency was due to the drive to base science on something firmer and prior in the subject’s experience.’⁵

As a consequence of its making use of psychology in its epistemological enterprise, a naturalist in epistemology has to make the assumption that there is an external world, and he ignores scepticism. However, an episte­mologist cannot disregard the question as to whether the grounds of science can be validated. It would clearly be circular reasoning if the epistemologist used science in his attempt to validate science. In regard to this problem Quine holds that ‘such scruples against circularity have little point once we have stopped dreaming of deducing science from observations.’⁶ However, as a consequence, the naturalist in epistemology can never arrive at a valid answer to the question whether the grounds of science can be validated.⁷ Naturalised epistemology presupposes science in order to solve the problem of knowledge; naturalised epistemology is built on this very presupposition. In making the presupposition about the existence of the resources of science and with that a presupposition about the external world, a naturalist in epistemology cannot possibly answer the epistemological question about the existence of the external world. The naturalist in epistemology assumes the existence of the external world.

Moreover, naturalised epistemology does not rule out the possibility that our view of the world around us is an illusion.⁸ Naturalised epistemology locates epistemology within natural science, and a scientist takes no notice of scepticism because otherwise he could not make much sense of his scientific work. Accordingly, a naturalist in epistemology cannot accept the sceptic’s wholesale doubt and, in contrast to the traditional episte­mologist, ignores scepticism.

However, nothing prevents the naturalist in epistemology from supple­menting his theory with additional independent philosophical arguments designed to refute scepticism and prove his assumption that there is an external world. And, indeed, Quine deploys such arguments which are perfectly compatible with naturalised epistemology.

One of these arguments points out that if scepticism is true, everything could turn out to be false and hence everything could be an illusion. Quine argues that if everything were an illusion, that is to say in the absence of any reality, there would be nothing to contrast illusion with. Furthermore, given the lack of such a contrast, the notion of an ‘illusion’ would, so to speak, cease to exist. Hence, scepticism is self-refuting.

Another argument Quine refers to is the ‘best explanation’ argument, according to which belief in the external world is justified because it provides the best explanation for the sensory data stimulating us. Moreover, to a certain extent at least some of our beliefs about the world are ensured as accurate because we are still alive; our beliefs are justified in a somewhat evolutionary sense. If we were constantly deceived, we would not be able to survive; for example it would be impossible to tell which food was poisonous if our beliefs did not to a certain extent match reality. Scepticism appears to be mistaken because beliefs seem to ‘work’. According to Quine, the existence of a persisting and rule-bound external world is ensured because it is the most plausible economic explanation which makes predictions about the future possible and allows scientists to do their job.

So the assumptions which underlie naturalised epistemology can be backed up by independent arguments, but as long as such arguments are not incorporated into the concept of naturalised epistemology, naturalised epistemology on its own does not address and hence does not answer traditionally important epistemological questions in relation to the existence of the external world and scepticism.

A second epistemological question to be considered relates to the justifi­cation of beliefs. The traditional epistemologist wants to know what the justifications are for our beliefs. He wants to know what good reasons for holding a belief are, and therefore asks a normative question.

A crucial difference between naturalised and traditional epistemology is that the data for naturalised epistemology are physical stimuli, whereas the data for traditional epistemology are conscious states. In the concept of naturalised epistemology consciousness seems to be excluded; being a conscious being is not a necessary condition for being a knowing being.

A naturalist in epistemology is interested in the route of causation which brings about the transformation from meagre input to torrential output; he isn’t interested in a justificatory route. He is paying attention to the causal relationship between sensory input and the belief that is formed on the basis of this input. He asks what the causes for our beliefs are. He seeks an answer to the question about why we believe what we believe.

Whether a belief is justified or not depends on whether the physical stimulus causing the belief is justified. Naturalised epistemology is not in a position to detect this. An unjustified physical stimulus is processed in exactly the same way as a justified one. From within naturalised episte­mology it is irrelevant whether a belief is justified or not. The traditional epistemological question of what justifies a belief is an independent subject matter from the perspective of a proponent of naturalised epistemology.⁹

To summarize, naturalised epistemology is concerned with the causal explanation of beliefs, and traditional epistemology with their justifi­cation.¹⁰ It seems as if naturalised epistemology is bound to leave un­answered the important traditional epistemological question of what justi­fies a belief. At first sight it seems as if Quine abandons norms altogether.

However, the statement that naturalised epistemology has nothing to contribute to and hence is not concerned with the question of whether a belief is justified can be challenged. Quine holds that the scientific approach is normative and argues that the normative is naturalised, not dropped. The normative can be located within the scientist’s factual realm; a normative question can be answered by appealing to factual issues, for example to facts about causation and probability. For example if we assume that a belief is caused by other beliefs and its truth value depends on the truth value of these causing beliefs, then a scientist can apply scientific concepts of causation and probability to investigate whether we ought to hold this belief. That is to say if a belief is produced by a reliable method, then it is entirely possible for a scientist to approach normative questions about this belief. In this case a scientist can, without ‘missing’ non-naturalistic concepts of justification, make normative judgements, because the normative can be naturalised.

From this perspective it seems as if it is necessary to modify the position, reached in the previous paragraph, that naturalised epistemology cannot account for normative epistemological questions. At least on the assumption that beliefs are produced by a reliable method it seems as if naturalised epistemology is not bound to leave unanswered the question about the justification of beliefs.

What important epistemological questions actually are is an issue which depends on the very nature of epistemological inquiry.¹¹ The concepts of naturalised and traditional epistemology are dissimilar; questions each can pose cannot be the same and, consequently, the set of answers each can provide is different. Critics like Rorty hold that ‘Quine dissolves a dilemma only by changing the motives of inquiry.’¹² Barry Stroud argues that it is important to distinguish Quine’s epistemological project from traditional epistemological concerns.¹³

According to some of these critics it might even be doubted whether naturalised epistemology should be called epistemology at all.

It was said earlier that naturalised epistemology is unable to answer some important epistemological questions if there was an area of epistemo­logical investigation which could only be approached in the traditional way. With regard to investigations into the justification of beliefs, natura­lised epistemology can provide us with an answer on the assumption that it is possible to naturalise the normative. However, in relation to the role of scepticism and to questions with regard to the existence of the external world, naturalised epistemology itself (that is to say without reference to other independent philosophical arguments) is not equipped to answer important epistemological questions. The epistemological questions naturalised epistemology cannot answer are the very questions which query the assumptions naturalized epistemology is built on. Hence it can be concluded that there are some epistemological questions which naturalised epistemology is bound to leave unanswered.

Bibliography:

Craig, E. (Ed.): Routledge Encyclopaedia of Philosophy; volume 3, Routledge, 1998

Everitt, N.; Fisher, A.: Modern Epistemology, A New Introduction; McGraw-Hill Inc., 1995

Koppelberg, D.: Why and how to naturalise epistemology; in Barret, R. B.; Gibson, R. F. (Eds.): Perspectives on Quine; Basil Blackwell, 1990

Kornblith, H.: In Defence of a Naturalised Epistemology; in Greco, J; Sosa, E. (Eds.): The Blackwell Guide to Epistemology, Blackwell Publishers, 1999

Quine, W.V.O.: Epistemology Naturalized in ‘Ontological Relativity and other Essays’; Columbia University Press, 1969; reprinted in: Kornblith, H. (Ed.): Naturalizing Epistemology; The Massachusetts Institute of Technology, 1985

Rorty, R.: Philosophy and the Mirror of Nature; Princeton University Press, 1980

Sosa, E.: Nature Unmirrored, Epistemology Naturalised; in Sosa, E. (Ed.): Knowledge in Perspective, Selected Essays in Epistemology; Cambridge University Press, 1991

Stroud, B.: The Significance of Naturalized Epistemology; in Kornblith, H. (Ed.): Naturalizing Epistemology; The Massachusetts Institute of Technology, 1985

Stroud, B.: The Significance of Philosophical Scepticism; Clarendon Press, 1984

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