Note 377 — Chapter V

It seems unnecessary to discuss separately the case in which a conditional premiss and a categorical premiss are combined: e.g., All selfish people are unhappy; If a child is spoilt, he is sure to be selfish; therefore, If a child is spoilt he will be unhappy. Such a syllogism as this is resolvable into an ordinary categorical syllogism by reducing the conditional premiss to the categorical form, “All spoilt children are selfish”; or it may be resolved into a conditional syllogism by transforming the categorical premiss into the corresponding conditional, “If anyone is selfish, he is sure to be unhappy.” The following is another example: If water is salt it will not boil at 212°; Sea water is salt; therefore, Sea water will not boil at 212°. Compare Mr F. B. Tarbell in Mind, 1883, p. 578. The hypothetico-categorical syllogism as above defined cannot be so summarily disposed of.