List, To Jon’s points in this post, which I think are well taken, I’d like to add a few remarks taken from Peirce’s Lowell Lecture 7 (1903), which might clarify the nature of the Peircean trichotomy of Arguments: Deduction/Induction/Abduction (a key feature of his “speculative grammar”). The full transcription of the lecture (R 473-4) is at http://gnusystems.ca/Lowell7.htm.
Peirce’s subject in this lecture, as in the entire Lowell series, is the process of scientific inquiry, or to put it most broadly, learning from experience. How are the three types of Argument involved in this? [[ You will see from what I have said that Deduction is decidedly the least important of the three. Deduction is merely a link by which the result of Abduction,— that is to say the proposed explanatory hypothesis,— is put into a form in which Induction can be applied to it; and it only consists in making thought distinct as to what the Supposition that the Abduction suggests really supposes. While it is a relatively insignificant step in the inquiry, however, Deduction becomes of surpassing importance in logic; and the reason of this is that Logic or rather Critic, which is that branch of logic that evaluates arguments, is itself Deductive. ]] In other words, abduction and induction — the generation and empirical testing of hypotheses — are the important types of argument for all positive sciences (including both cenoscopy and idioscopy). The critical role of Deduction (“necessary reasoning,” formal or mathematical logic) is to provide a kind of metalanguage which enables us to evaluate our abductive and inductive arguments, which draw conclusions that are not necessary but which are self-correcting enough to lead us toward the truth in the long run. This is quite different from saying that all theories can be stated in formal-logical terms, because those terms are not indexically anchored to the objects of scientific theories, as inductive logic is. Gary f. } Everything is always becoming something other than what it was becoming. [Floyd Merrell] { <http://gnusystems.ca/wp/> http://gnusystems.ca/wp/ }{ Turning Signs gateway From: Jon Alan Schmidt <jonalanschm...@gmail.com> Sent: 15-Sep-18 21:56 To: peirce-l@list.iupui.edu Subject: Re: [PEIRCE-L] Categories and Modes of Being John S., List: JAS: As Peirce put it later in the same manuscript, "mathematics is the science which draws necessary conclusions," while logic is the (normative) "science of drawing necessary [and other] conclusions" (CP 4.239; 1902). JFS: Those additions put words in Peirce's mouth. Peirce said here that deductive logic is "the science of drawing necessary conclusions," but he elsewhere (and repeatedly) also recognized inductive and retroductive logic as having their own validity, despite drawing conclusions that are not necessary. All three fall under Critic, the middle branch of the Normative Science of Logic as Semeiotic; in fact, as I quoted previously, Peirce stated explicitly in the very next paragraph that logic "is a normative science" (CP 4.240; 1902). JFS: Since he wrote that classification in 1902, he probably wasn't as careful about the his 1903 distinction between formal logic and normative logic ... Since Peirce wrote this passage in 1902 -- before he classified (non-formal) logic as a normative science -- he was talking about formal logic. Again, these statements are directly falsified by CP 4.240; for Peirce, logic was already "a normative science" in 1902. CSP: The logician does not care particularly about this or that hypothesis or its consequences, except so far as these things may throw a light upon the nature of reasoning. (CP 4.239; 1902) JFS: That is the opposite of the normative logician, who cares very much about hypotheses and their consequences. That seems like a clear misreading of the quote. In context, Peirce was talking about mathematical hypotheses and their consequences, which need not (and often do not) have any bearing on Reality whatsoever. Mathematicians just want to derive those consequences as efficiently as possible, but the normative logician studies "the nature of reasoning"--i.e., "deliberate thinking"--in minute detail. Regards, Jon Alan Schmidt - Olathe, Kansas, USA
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