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Some hard questions for Critical Rationalism
by David Miller
Overview
Six hard questions for Critical Rationalism
0. Introduction
"It will be taken for granted, however, that for the problem of demarcation, which Popper called `the central problem ... of the theory of knowledge', and for the problem of induction, widely regarded as the fundamental problem of the philosophy of science, brilliant solutions already exist."
1. Demarcation and Induction
"It will be taken for granted, however, that for the problem of demarcation, which Popper called `the central problem ... of the theory of knowledge', and for the problem of induction, widely regarded as the fundamental problem of the philosophy of science, brilliant solutions already exist."

These are both, according to Miller, solved problems, and the solution in both cases is "much as Popper solved it".

They are mentioned by Miller primarily so that he can clear up various common misunderstandings of Popper's solution to these problems (often it appears, partly provoked by Poppers own writings).

This he aims to do by clarification of the nature of these two problems.

The Problem of Demarcation

It is not:

  • to `distinguish scientificc and non-scientific matters in a way which exhibits a surer epistemic warrant or evidential ground for science than for non-science'
  • `to explicate the paradigmatic usages of "scientific"
  • concerned with questions of usage, classification, or status
But instead of an explicit statement of what the problem is, we get:
"the main problem of the theory of knowledge, at least for an empiricist, is quite different in kind: it is what Popper described as `the critical analysis of the appeal to the authority of experience'"
But also:
"Popper's philosophy is potently and expressly opposed to all these fashionable tendencies, and to all visions of science as `a body of knowledge' exciting awe and deference and enjoying magisterial authority"
Which is nice, but still doesn't tell us what the demarcation problem is.

However, later we have an explicit statement of the problem:

under what circumstances is an empirical investigation worth undertaking?
So it sounds like the aim is to distinguish empirical theories (though the above formulation incorporates a judgement about whether the theory is worth investigation, not just whether an investigation would be empirical)..

The Problem of Induction
"The principal deductivist insight here is that since ampliative (that is, inductive) inferences are invalid, their conclusions are no better supported than unsupported guesses, obtusely resistant to justification but, it is to be hoped, acutely susceptible to refutation."
2. Six Hard Problems
2.0 Is progress possible if our knowledge is always contradictory?

In the statement of the problem here, it appears that it is not just contradictory "knowledge" but contradictory hypotheses which are involved.

Miller's seems to think paraconsistent logics may help with this problem.

2.1 To what truths do approximate truths approximate?

Talk here of metrics which define the distance between theories.

Apparently we must distinguish between falsification and rejection, and be prepared to chose on some basis between theories both of which have been falsified,

2.2 Does a disproof require a death sentence?

Apparently we are not expected to abandon a theory just because it has been falsified. A falsified theory may nevertheless represent some kind of approximation to the truth. What Miller is looking for here is some way of measuring how closely some falsified theory approximates the truth, for use in the application of science.

Popper has some ideas about verisimilitude which are now thought unsatisfactory. Miller offers a "solution" which seems to depend on there being a probability function which tells us the probability of each proposition, in terms of which he defines a measure of the degree of approximation of a proposition to the truth.

2.3 What do you do if you don't have knowledge?

This seems to be about how to make practical decisions about the future on the basis of known science.

2.4 Does a death sentence require a proof?

This really is about death sentences, and the proof in question is a proof of guilt of some capital crime.

What Miller is looking for here is a way of replacing the idea of proof in courts of law with the "deductivist" alternative of a notion of a deduction of guilt from the presented evidence which survives the critical scrutiny of the defence lawyers (in a way which would be acceptable to the legal profession).

2.5 FOr want of a nail...

3. Conclusion


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Created:2009-09-20

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