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century the best of my energies have been devoted to learning all I could about reasoning; and now it is high time I gave the benefit of what I have learned to those who care to make the necessary effort to comprehend it.
I mean to consider them exclusively.
Therefore these lectures will requre close attention and a certain effort of thought.

I shall consider all the main classes of reasoning, Deductive, Inductive and Abductive, as fully as I can do in do very short a course, paying the smallest possible attention to pure theory but dwelling on the precautions necessary to be observed in practice.
Mathematical reasoning, which is the easiest kind of reasoning, and which is essentially involved in all reasoning, will command our attention first.