John C, John S, List, Kant's lectures on logic and his remarks in the three Critiques make it clear that he recognizes and appreciates inference to hypothesis and inference by induction as forms of argument that are different in kind from deductive inferences such as demonstrative reasoning.
In the Lectures on Logic, such as the late collection called the Jäsche lectures, Kant seems to claim that the validity of both forms of synthetic inference is only "psychological" in character. Having said that, it is difficult to determine from the context of the Jäsche lectures whether that is Kant's own position, or whether it might be a position that he is simply describing as a view that is articulated in the textbook on logic (by another author) that he is discussing with his students. What does seem clear is that Kant tried to justify the validity of synthetic forms of cognition by focusing on the justification of the judgments. Peirce, on the other hand, focuses on the patterns of inference, and claims that the logical justification of these inferences should be based on the formal relations between the propositions that make up the premisses and conclusions. It is a mistake, Peirce thinks, to confuse matters of judgement (which do involve psychological issues) with matters of assertion, the truth of propositions asserted and the formal relations between those propositions. --Jeff Jeffrey Downard Associate Professor Department of Philosophy Northern Arizona University (o) 928 523-8354 ________________________________________ From: John Collier [[email protected]] Sent: Monday, January 30, 2017 8:01 AM To: John F Sowa; [email protected] Subject: RE: [PEIRCE-L] Nominalism vs. Realism Quite, John. I could have been more clear about that, but composing posts on my phone is tedious, and I kept it short. John Collier Emeritus Professor and Senior Research Associate Philosophy, University of KwaZulu-Natal http://web.ncf.ca/collier > -----Original Message----- > From: John F Sowa [mailto:[email protected]] > Sent: Monday, 30 January 2017 4:33 PM > To: [email protected] > Subject: Re: [PEIRCE-L] Nominalism vs. Realism > > > Peirce's contribution was to recognize that Kant's synthetic a priori could be > replaced by abduction. Then he called it a method of reasoning at the same > level as induction and deduction. The problem of justifying a particular > abduction is a matter for the philosophy of science. > > John F.S.
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