The Logic of Real Arguments

The Logic of Real Arguments is the title of a Cambridge University reference work by Alec Fisher, first published in 1988. I’m reading the 2004 second edition in response to a request from Lee Beaumont to help with some Wikiversity course material on clear thinking. The best basis of good real-life decisions is of course my main topic so I was intrigued to read a title I’d not come across before.

I’m starting with little hope of finding any magic bullet, but the book itself starts well. Formal logics are relegated to an appendix, so the author can launch in with what really needs to be known – it starts epistemological. In summary:

• Don’t worry about definitions of terms until later – (“hold your definition” as Dan Dennett would say) – they will ultimately be worked out in the process. Just follow your intuition and common sense understanding of reason.
• Grasp the outlines of what is being argued, like definitions, we can refine and add qualifications later. There are methods and frameworks but real argumentation is not mechanical or algorithmic, it’s always more complicated.
• Not only are the actual assertions, premises, reasoning and conclusions often entirely implicit in real natural language arguments, but interpreting any of these also depends on understanding the apparent but implicit and subjective intentions of whoever is making the case. Implication and intent are always ambiguous, so always default to charity with respect to the quality of the argument. Assume the best, aim to agree where possible. Analyse and test on that basis.
• [Aside – one of Fisher’s references is Stephen Toulmin’s (1958) The Uses of Argument. Toulmin’s (1990) Cosmopolis and (2001) Return to Reason have been influential on my own journey.]

So far so good.

In fact it seems inexorably to be leading to my own conclusion, that no amount of careful – even formal – logical argumentation will be 100% right outside of an artificially bounded control volume under laboratory conditions. ie never in real life arguments. No real argument can be completely consistent.

Gödel already tells us this.

The bad news is most of the rest of the book is analytical. I guess that figures, if your objective is to teach students what’s wrong. So-called critical thinking aimed at dissecting the arguments of others. Lots of classic examples – Galileo’s included – to analyse and hone those cutting skills, but so far no obvious alternatives for what makes a “good” real-life decision-making rationale?

One example of Fisher’s classic examples is A J Ayer’s logical refutation of Descartes mind-matter duality. Obviously he was right to refute it since Cartesian duality is obviously wrong, and it’s a good example to understand how Ayer demonstrated that. Proving people wrong, finding fault with the arguments of others is easy. Unfortunately Fisher’s own conclusion is worrying.

“[Ayer’s] absolute division between science and philosophy is a mistake.”

Well no. Ayer makes no such error, what he actually says is:

“[The manner] of conceiving the distinction between mind and matter is at fault. In short our problem is not scientific but philosophical”

Clearly what Ayer intends “in short” is nothing “absolute”, more:

… not [wholly] scientific but [also at least in some part] philosophical.

Whatever happened to charity, Mr Fisher?

Anyway, after more examples, including Popperian and Kuhnian bases for good scientific arguments, Fisher concludes with what has been his main focus from the start – the philosophy of his Assertability Question, which asks:

What …. would justify me in asserting C? or

What would I have to know or believe to be justified in accepting C?

It’s about epistemology. It’s about – what. It’s not about – is. It’s not about – is C true or false?

It does not ask anything about proving truth or falsity.

Which probably explains why the formal logical tools and methods are relegated to an appendix. They are merely tools in the hands of the wise. Tools (knives & files, like Aristotle’s analytic knife and Okham’s razor) contain constraints, but no intrinsic wisdom. We murder to dissect.

Which is pretty much the conclusion of this three-way discussion on The Limits to Logic from 2014 (5th talk lower down). Logic is a useful tool for testing consistency, but is never sufficient for a complete rationale – Gödel again – and even when demonstrating inconsistency, it can’t actually help you decide if the assertions, the conclusion or the underlying model & premises are necessarily wrong.

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Post Notes:

It’s complicated:

And this (apparently serious?) summary of how to interact with philosophers, seems to cover some of the same key ground – especially the broad agreement BEFORE detailed analytical dissection. And charity – make the effort to understand the philosopher’s actual motives and avoid presumptious (accidental) ad-hominem criticism.