Obversion consists in negating the second term of a proposition and changing its quality. Contraposition consists in negating both terms and reversing their order. O nbna . Inversion consists in inferring from a given proposition another having for its subject the negation of the original subject. I nanb .
Syllogisms draw a conclusion from two premisses.
We will use b to signify the middle term, a and c to signify what are called the extreme terms. Those who vote for their own unemployment are fools to themselves. Any workers who voted for that party are fools to themselves. Traditionally syllogisms were set out this way, with the conclusion under the premisses like the lines of a sum. Those who profess such a thing but do nothing about it are not practising what they preach.