An outline of the necessary laws of thought: (1860) PDF book by William Thomson
a treatise on pure and applied logic
The present work is an attempt to enlarge the science of Pure Logic, so that it may be adequate to the analysis of any act of reasoning. How far it has attained its object ought to be decided by the application of its principles to many miscellaneous examples from different sciences; and whilst I have rigorously and frequently applied this test to it for many years, I cannot hope that the partiality of an author will be a sufficient guarantee of its pretensions, and therefore commend the same line of examination to anyone who believes, with me, that a sedulous practice of logical analysis will richly reward the understanding with accessions of strength and clearsightedness. If the result should be the detection of many errors and omissions on the author’s part, enough of matter may perhaps be left unshaken, to prove that Pure Logic is not the mere Officina veteramentaria the warehouse of useless relics it is too often taken for, but a practical system an important branch of mental culture.