This is really two distinct hypothetical judgments, associated because they happen to have a common term "the criminal;" and because one or other of them must be true; and two distinct syllogisms would be founded upon them, as the counsel for the defence would probably take for his second premiss"He did not know the consequences of his act, therefore he is insane," while the counsel for the prosecution would maintain that "He did know the consequences, and therefore was guilty." No doubt it is a great detriment to a prisoner to be found either guilty or insane, but this does not appear upon the face of the argument, and therefore pure Logic does not take it into account. A new judgment would be required to show the connexion of the two notions; so that besides the two conditional syllogisms, contained in the argument itself, a third is tacitly admitted, that shows the connexion of the other two. This sort of argument, a great favourite with the Sophists and old logicians, is called also Syllogismus Crocodilinus, and Syllogismus Cornutus; and "the horns of a dilemma" are known even to common language.

§ 110. Incomplete Syllogisms.

The arguments used in thinking, speaking, or writing, are never drawn out in strict technical form,

except by practised logicians, desirous of exhibiting their art to those who, like themselves, are conversant with it. A sentence which contains the materials of a syllogism, not technically expressed, has been called an enthymeme, or an enthymematic sentence. Aristotle understands by enthymeme a syllogism such as would be used in rhetoric where the full and orderly expression of premisses and conclusion would seem laboured and artificial. And as the omission of one of the premisses is a common, perhaps the commonest, feature of enthymemes, logicians have defined them as syllogisms with one premiss suppressed. But we may also omit the con

clusion, or invert the order of premisses and conclusion; and unless we extend the name enthymeme to these cases we put a considerable restriction upon its original meaning. Let the enthymeme then be defined-an argument in the form in which it would naturally occur in thought or speech.

§ 111. Prosyllogism and Episyllogism.

In a chain of reasoning, one of the premisses of the main argument may be the conclusion of another argument, in that case called a prosyllogism: or the conclusion of the main argument may be a premiss to a supplementary one, which is called an episyllogism. Let us take the syllogism which a coroner's

jury might have to go through. The question is, "Has A. B. been poisoned?" and the syllogism is, "A man who has taken a large quantity of arsenic has been poisoned, and A. B. is found to have done so, therefore he has been poisoned;" with the addition of a prosyllogism and episyllogism the reasoning would run"A man who has taken arsenic has been poisoned; and A. B. has taken arsenic, for the application of Marsh's and Reinsch's tests discover it (Prosyl.); therefore A. B. has been poisoned, and therefore we cannot return a verdict of death from natural causes." (Episyl.) A prosyllogism then is a syllogism whose conclusion is a premiss in a given syllogism; an Episyllogism is one, whose premiss is a conclusion in a given syllogism. The Sorites, Prosyllogism and Episyllogism, deserve our attention as the joints of thinking by which the various members, the acts of immediate and mediate inference, are knit together in an organic connexion. Of them, however, the first can rarely be employed; the two last meet us continually.

"Mais, parce que l'esprit se laisse quelquefois abuser par de fausses lueurs, lorsqu'il n'y apporte pas l'attention nécessaire, et qu'il y a bien des choses que l'on ne connâit que par un long et difficile examen, il est certain qu'il serait utile d'avoir des règles pour s'y conduire de telle sorte, que la recherche de la vérité en fût et plus facile et plus sûre; et ces règles, sans doute, ne sont pas impossibles.”— "-ARNAULD.