An answer to the gap problem (?)

Brown, J. (2011). Thought experiments, intuitions and philosophical evidence. Dialectica, 65(4), 493-516.

The paper starts as follows: “What is the nature of evidence provided by thought experiments in philosophy?” What is surprising, then, in view of this undertaking, is that none of the towering literature on this matter is quoted or used. Unfortunately, instead of providing a fresh approach on this old chestnut, the conclusions supported in the paper are rather unsophisticated.

Brown identifies the problem as follows:

the psychological proposition that it seems to me as if the Gettier subject has a non-knowledge justified true belief is not in itself a counterexample to the JTB theory of knowledge. A genuine counterexample would be a case of justified true belief which is not knowledge (Brown, 2011, p. 500)

So yes, the old intuition-pumps criticism put forward by Daniel Dennett. If thought experiments are based merely on “what one would say” or “what one would feel” or “what one would accept” in the depicted scenario, how can we use thought experiments to support those solid, difficult, objective theories? Using Brown’s terminology, and putting it a bit crudely, how can psychological facts support non-psychological propositions? The assumption underpinning the relevance of this question is that there is a gap (of the subjective/objective kind).

there is a gap between one’s perceptual evidence and what it is taken to be evidence for, in the sense that the proposition that one is having an experience as of p does not entail that p is the case.

Brown diligently considers many views and viewpoints on this matter and some other ones more or less related. She spends a lot of time with the similar problem of perception (how can perception justify theoretical knowledge? etc.)

Finally, her answer is this. I’m quoting it because I don’t understand it.

one could close this apparent gap by appeal to an externalist approach to justification and/or knowledge. Suppose that whenever one has such an experience, one forms an appropriately related belief. For instance, that when one has an experience as of a large barking dog in front of one, one forms the belief that there is a large barking dog in front of one. On an externalist approach to justification, such as reliabilism, as long as the appropriate external relations hold, the beliefs so formed are justified.

One might hope to apply this solution to the gap problem in the case of perception to the gap problem facing the psychological view of thought-experiment evidence. Suppose that, in fact, the method of forming beliefs about the nonpsychological subject matter of philosophy on the basis of the relevant psychological propositions is reliable. Combining this supposition with a reliabilist approach to justification has the result that beliefs formed in this manner are justified (p. 513)

I honestly do not see what this “combination” means. I understand she is saying this: “Well, remember how subjective propositions can support subjective propositions? Take that, and apply it to our situation, where subjective propositions must support objective ones and say that the appropriate external relations must hold”. But how is this an answer to the problem? One should immediately respond: “Well sure, there must be some extra conditions applying to this step since we know that sometimes subjective/psychological data is misleading and leads to unjustified objective/non-psychological data. We know that. We know that not all of those inferences are justified and we know that the ones that are justified are as such in virtue of the criteria. But the question here concerns precisely these criteria. It is no news nor solution to say – ‘Well, you see, some criteria must hold, criteria concerining the passing from the subjective to the objective’”.

All in all, I guess, this boils down to answering the question of expertise: When is appeal to expertise to be trusted? Because, in thought-experiments that appeal to intuitions – if there are such things, and I think there are – it is the philosopher’s claim to his expertise on one’s intuition that functions as argument.

Unfortunately, it might turn out that no universal answer is possible and that the criteria are highly field-dependent.