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modes of the first figure in which the major is particular, do not conclude, he proceeds thus: " If "A is or is not in some B, and B in every C, no "conclusion follows. Take for the terms in the "affirmative case, good, babit, prudence, in the negative, good, babit, ignorance." This laconic style, the use of symbols not familiar, and, in place of giving an example, his leaving us to form one from three assigned terms, give such embarrassment to a reader, that he is like one reading a book of riddles.


Having thus ascertained the true and false modes of a figure, he subjoins the particular rules of that figure, which seem to be deduced from the parti cular cases before determined. The general rules come last of all, as a general corollary from what goes before.

I know not whether it is from a diffidence of Aristotle's demonstrations, or from an apprehension of their obscurity, or from a desire of improving upon his method, that almost all the writers in lo gic I have met with, have inverted his order, beginning where he ends, and ending where he be gins. They first demonstrate the general rules, which belong to all the figures, from three axioms then from the general rules and the nature of each figure, they demonstrate the special rules of each figure. When this is done, nothing remains but to apply these general and special rules, and to reject every mode which contradicts them.

This method has a very scientific appearance: and when we consider, that by a few rules once demonstrated, an hundred and seventy-eight false modes are destroyed at one blow, which Aristotle had the trouble to put to death one by one, it seems to be a great improvement. I have only one objection to the three axioms.

The three axioms are these: 1. Things which agree with the same third, agree with one another. 2. When one agrees with the third, and the other does not, they do not agree with one another. 3. When neither agrees with the third, you cannot thence conclude, either that they do, or do not agree with one another. If these axioms are applied to mathematical quantities, to which they seem to relate when taken literally, they have all the evidence that an axiom ought to have: but the logicians apply them in an analogical sense to things of another nature. In order, therefore, to judge whether they are truly axioms, we ought to strip them of their figurative dress, and to set them down in plain English, as the logicians understand them. They amount therefore to this. 1. If two things be affirmed of a third, or if the third be affirmed of them; or if one be affirmed of the third, and the third affirmed of the other; then they may be affirmed one of the other. 2. If one is affirmed of the third, or the third of it, and the other denied of the third, or the third of it, they may be denied one of the other.

3. If both are de

nied of the third, or the third of them; or if one is denied of the third, and the third denied of the other; nothing can be inferred,

When the three axioms are thus put in plain English, they seem not to have the degree of evidence which axioms ought to have; and if there is any defect of evidence in the axioms, this defect will be communicated to the whole edifice

raised upon them.


It may even be suspected, that an attempt by any method to demonstrate that a syllogism is conclusive, is an impropriety somewhat like that of attempting to demonstrate an axiom. In a just syllogism, the connection between the premises and the conclusion is not only real, but immediate; so that no proposition can come between them to make their connection more apparent, The very intention of a syllogism is, to leave nothing to be supplied that is necessary to a complete demonstration. Therefore a man of common understanding, who has a perfect comprehension of the premises, finds himself under a necessity of admitting the conclusion, supposing the premises to be true; and the conclusion is connected with the premises with all the force of intuitive evidence. In a word, an immediate conclusion is seen in the premises, by the light of common sense; and where that is wanting, no kind of reasoning will supply its place.



SECT. 5. On this Theory, considered as an Engine of Science.

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The slow progress of useful knowledge, during the many ages in which the syllogistic art was most highly cultivated as the only guide to science, and its quick progress since that art was disused, suggest a presumption against it; and this presumption is strengthened by the puerility of the examples which have always been brought to illustrate its rules.

The ancients seem to have had too high notions, both of the force of the reasoning power in man, and of the art of syllogism as its guide. Mere reasoning can carry us but a very little way in most subjects. By observation, and experiments properly conducted, the stock of human knowledge may be enlarged without end; but the power of reasoning alone, applied with vigour through a long life, would only carry a man round, like a horse in a mill who labours hard but makes no progress. There is indeed an exception to this observation in the mathematical sciences. The relations of quantity are so various and so susceptible of exact mensuration, that long trains of accurate reasoning on that subject may be formed, and conclusions drawn very remote from the first principles. It is in this science and those which depend upon it, that the power of reasoning triumphs; in other matters its trophies are inconsiderable.

siderable. If any man doubt this, let him produce, in any subject unconnected with mathematics, a train of reasoning of some length, leading to a conclusion, which without this train of reasoning would never have been brought within human sight. Every man acquainted with mathematics can produce thousands of such trains of reasoning. I do not say, that none such can be produced in other sciences; but I believe they are few, and not easily found; and that if they are found, it will not be in subjects that can be expressed by categorical propositions, to which alone the theory of figure and mode extends.

In matters to which that theory extends, a man of good sense, who can distinguish things that dif fer, can avoid the snares of ambiguous words, and is moderately practised in such matters, sees at once all that can be inferred from the premises : or finds, that there is but a very short step to the conclusion.

When the power of reasoning is so feeble by nature, especially in subjects to which this theory can be applied, it would be unreasonable to expect great effects from it. And hence we see the reason why the examples brought to illustrate it by the most ingenious logicians, have rather tended to bring it into contempt.

If it should be thought, that the syllogistic art may be an useful engine in mathematics, in which pure reasoning has ample scope: First, it may be observed,

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