“To answer these questions we seem first to need an answer to the question ‘What is logic?’
My own belief is that there is no fact of the matter about what entitles a theory of reasoning to logical status, and one has to proceed as one does in extending common law to new cases, by appeal to precedent and common sense. Here again, of course, one must be selective, but with modern deductive logic in mind I propose the following as necessary and sufficient conditions for a discipline to have the status of logic:
( a) It involves statements and relations between them.
( b) It adjudicates some mode of non-domain-specific reasoning.
( c) It is ‘about consistency’. More specifically, it should incorporate a semantic notion of consistency which can be shown to be extensionally equivalent to one characterizable purely syntactically; this equivalence is the content of what are called soundness and completeness theorems for the corresponding system. First-order logic famously has a soundness and completeness theorem.”
The quote above has profound implications for the author (the red highlight is my emphasis). And it is an issue I rarely see addressed by anti-theists such as this author. If there is in fact no mechanism to entitle one theory of reasoning to logical status, then such would be the destruction of all human predication. Obviously Howson is wrong. In order for the paragraph (or the book for that matter) to have any real value, he must assume that there is in fact a way to entitle his preferred manner of reasoning to logical status. If not, what would be the point? Debate would be inevitably stultified in that your opposition need only adopt any other contrary form of reasoning which one has elevated to logical status.
Howson’s proposal of the three conditions above as necessary and sufficient are no more arbitrary than Kant’s proposed necessary conditions for which he grounded his transcendental argument. Howson has already critisized Kant for doing this.
The problem with Kant’s theory is the undeniable fact that we can sensibly and consistently conceive alternatives to the principles Kant held to be ‘necessary’ conditions of cognizing
That of course is true. But it is also true for Howson’s proposed criteria above. The fact that competing paradigms of logic exist demonstrates that Howson is no less arbitrary than Kant and arbitrariness is the opposite of necessity.