Resources

Additional Reading

Validity as Argument

• Toulmin, S. E. (2003) The Uses of Argument. Cambridge: Cambridge University Press.

Originally published in 1958, this is a philosophical text that deals with logic, and how we arrive at conclusions. It does not delve into the differences between deductive, inductive and hypothetical reasoning, although there is an introduction to the various approaches to arriving at conclusions from premises. What the book does it to start from the assumption that in most cases there is a level of probability involved in arriving at a conclusion from the premises in the argument. If the premises contain 'facts' then it is uncertain that our conclusions flow without question from these facts, and the 'argument' that they do depends upon the strength of the case that we make for our argument. In everyday life we don't often think about what constitutes a good argument, or formulate our arguments formally. But when conducting research, and especially when thinking about validity, approaching the problem formally has many advantages. And so we recommend this book as excellent reading for those with an interest in the philosophical side of language testing. Toulmin's central thesis is summarized powerfully on page 7, where he writes: "Logic is concerned with the soundness of the claims we make – with the solidity of the grounds we produce to support them, the firmness of the backing we provide for them – or, to change the metaphor, with the sort of case we present in defence of our claims."

There are also ample resources on logical argumentation available on the web, including (but not limited to):

• Wikipedia's treatment of logical argument
• The Philosophy Pages
• A List of Fallacious Arguments (from the Science and Skepticism page)

There are many more, which you can find by searching terms like 'logical argument', 'logical fallacy', 'logical reasoning', and even simply 'logic'. It is all a bit overwhelming at times, but then, testing is a latecomer to logical reasoning. Not too long ago, validation was a set-piece in the testing drama, as Chong Ho Yu points out at his historical overview. Things seem more difficult now, or perhaps (in a curious way) rather easier: maybe validation is the argument that works, that is persuasive, that convinces the reader or listener that sufficient evidence has been assembled that the inferences from the test are sound.