It is more often the case that is dubious. 'If Caius is a European _he is white_, for all Europeans are white.' 'If Damon is in town _Pythias is in town_, for they are inseparable.' 'If I were you _I should defer the voyage to the summer season_, as I have always found winter travelling disagreeable.' But the word 'if' does not always mark a hypothetical thought. In the proposition, 'if children are neglected they will grow up ignorant,' we have a dogmatic or assertorial judgment--'neglected children grow up ignorant.' (Bain.) The precedent may be suppressed in hypothetical as in dogmatic argument. 'If the crops are good, corn will be cheap' implies the unspoken precedent, 'good crops have been invariably followed by cheap corn.' 'If logic is useless it deserves to be neglected,' carries the mind to the more general thesis, 'all useless studies deserve to be neglected.' 'If Great Britain should be invaded the volunteers will be called out,' rests on the precedent judgment, 'it is the duty of the volunteer army to repel invaders.' Arguments in which both applicate and case are hypothetical are so very dubious that they cannot be considered of any practical use. '_If_ opium is poisonous, and _if_ this substance is opium, you will be poisoned by taking this substance.' The Aristotelian hypothetical is almost invariably a fallacy, sometimes on more than one account. It usually consists of--first, a conditional or doubtful statement; next, a solution of the doubt by means of positive information; finally and by way of inference the first statement is given without the doubt. Here is an example from Jevons: 'If the barometer is falling, bad weather is coming; but the barometer is falling; therefore bad weather is coming.' Where did the information that the barometer is falling come from? If we knew it before uttering the first proposition, we were affecting an ignorance that did not exist. The second proposition takes away all occasion for argument; it is an amendment of the first proposition, and what we get from the theorem as a whole is a _case_, followed by a prediction for which there is no precedent justification. We are arguing in a circle. 'If Aristotle is right, slavery is a proper form of society; but slavery is not a proper form of society; therefore Aristotle is not right.' If we knew for certain (as the second proposition indicates) that slavery is not a proper form of society, what is the use or meaning of treating the question as hypothetical (as is done in the first)? If we acquired the information after uttering the first proposition, there was no occasion to go on with the argument; we should have said simply, 'Slavery is not a proper form of society, though Aristotle said it was.' It is needless, except for verbal completeness, to say 'he was not right'--we have _logically_ said so.