John Sowa, List
I agree with the points you make. Having said that, abductive inferences involve premisses and conclusions that may be expressed as interrogatives and/or investigands. I am particularly interested in the question of what the "toothbrush" icon represents and how that logical notion might be better expressed in later version of the EG. Many systems of logic do not have the power to express premisses or conclusions that articulate questions or lines of investigation. What is more, they don't have the ability to express a conclusion of an abuctive argument as being plausible. As such, they are not well suited for the task of analyzing the logical character of these signs. The gamma graphs, I take it, are designed to remedy these sorts of shortcomings. --Jeff Jeffrey Downard Associate Professor Department of Philosophy Northern Arizona University (o) 928 523-8354 ________________________________ From: John F. Sowa <s...@bestweb.net> Sent: Sunday, December 13, 2020 8:27:37 PM To: Jeffrey Brian Downard Cc: peirce-l@list.iupui.edu Subject: Re: [PEIRCE-L] Representing Abduction in the EG Jeff, All versions of logic, by Peirce and by any logicians before or after Peirce, represent propositions. Induction, abduction, and deduction are operations that relate propositions to one another in various ways. Those operations can be performed in equivaent ways with any notation for logic -- or even with propositions stated in English or any other language. JBD> It is an interesting question: how might one represent abductive inferences in the EG? Short answer: Peirce stated rules of inference for deduction with EGs. He also wrote a great deal about induction and abduction with examples stated in English. To adapt those examples to EGs, translate the English to EGs and then perform the equivalent operations on the EGs. John
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