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 2015-04-12 Contra Searle on Rules Gerald HullState University of New York at Binghamton John Searle is one of my favorite philosophers, but I fear remarks he makes in Rationality in Action about the role of rules in logic qualify as veritable "howlers".  He writes:The correct thing is to say that the rules of logic play no role whatever in the validity of valid inferences.  The arguments, if valid, have to be valid as they stand.  (20).But how is it that we determine when arguments are "valid as they stand"?  That is, how do we tell whether they have that all-important truth-preserving character?  I know I use rules of logic, rules like modus ponens, viz. "protasis, conditional, apodosis" (conveniently representable symbolically as "(p&(p->q))->q").Is there some other useful way of determining validity in an argument?  Surely there is no way of identifying validity apart from identifying truth-preservingness, and how do you identify truth-preservingness without alluding to some kind of rule?  In particular, how would you show that a mathematical proof is valid without talking about permissible rules of inference?Pace Dodgson's Tortoise, rules of logic like modus ponens are not premises from which one might infer whether an argument is valid, but are rather part of the very measure of that validity.  And, I submit, the public availability of such rules is intrinsic to the very objectivity of logic.  So instead of playing no role, the rules of logic play the role in determining validity.  Am I wrong? Permanent link: https://philpapers.org/post/9850 Reply

 2015-04-14 Contra Searle on Rules Reply to Gerald Hull I'm not a logician, but my two cents anyway:There is Wittgenstein's Tractarian view which seems to deny any justificatory role to rules of logic, eg., 5.132.You seem to be using "determine" in two different senses, first in the sense of identifying when arguments are valid, secondly in the sense of constituting validity. It's not clear to me how you move from the first sense to the second. If I use the truth-table method to determine truth-preservingness or validity, do I need to know rules like modus ponens or disjunctive syllogism? Permanent link: https://philpapers.org/post/9854 Reply

 2015-04-14 Contra Searle on Rules Reply to Gerald Hull Curt DoolittlePropertarian Institute Your confusion is common. Inference vs deduction.We can deduce logically within any tautology (in any axiomatic system), because the information is complete.We can identify contradictions logically (in both axiomatic and rational systems), where information is sufficient to do so.We cannot *infer* logically, we can only *theorize* logically.  That is the limit of what logic can do for us: assist us in the test of internal consistency and non-contradiction (an act of criticism or falsification), and assist us in the formation of theories.In addition, once we construct a theory, we can test a theory:- We can test for external correspondence (empiricism)- We can attempt to falsify by external correspondence. (parsimony)- We can test for existential possibility. (Operational Definitions, Operationalism, Operationism, Intuitionism) and that we are not substituting imaginary information.- We can test for morality (the absence of involuntary transfer, Propertarianism)And even then, when we have done our due diligence in internal consistency, external correspondence, attempts at falsification (parsimony), existential possibility free of imaginary substitution, There are no non-tautological, non-trivial, and therefore certain premises.  As such, the limit of logic (and why people like me criticize formal logic when used for other than the its narrow utility)  is in either falsification of statements, or the construction of theories that can be further tested. But you cannot determine truth propositions of non-tautological non-trivial propositions by logical means.The function of logic is criticism, not truth.  Once exhaustively criticized, you can say an argument or proposition is valid in the sense that it is well constructed. But this says nothing about the truth of the argument or proposition. It says only that it is well constructed.  Curt Doolittle The Propertarian Institute Kiev, Ukraine. Permanent link: https://philpapers.org/post/9857 Reply

 2015-04-14 Contra Searle on Rules Reply to Gerald Hull Eetu PikkarainenUniversity of Oulu I would interpret Searle so that logical rules may describe valid inferences, but the validity of those inferences is not (in some strong sense) based on those rules. That leaves place for us to use rules to determine whether some inference is valid or rather explicate why it is not valid. He writes: I am not saying that there could not be any rules to help us in rational decision making. On the contrary there are many famous such rules and even maxims. (22) (Though not explicitely referring to logical rules, but I see no reason why it should not contain also them.)Perhaps this is also connected to the Brandom's stress on the role of material infenrence in rationality? Similarily Searle points to the semantic content of inferences (in human rational action). Permanent link: https://philpapers.org/post/9859 Reply