its object the proper conduct of the understanding in judging and reasoning, it may therefore be proper to notice some of the causes of error. The following are a few of them: In their opinions, men are prone to be led too much by authority. There is in us a disposition to measure things less known and less familiar, by things more known and more familiar. We are often led into error from a love of simplicity, which disposes us to reduce things to few principles, and to suppose a greater simplicity in nature than really exists.

One of the most copious sources of error in philosophy, is the misapplication of our noblest intellectual power to purposes for which it is incompetent. In avoiding one extreme, we are very apt to go to the opposite. Our judgments are often perverted by our affections and passions.

Of Reasoning.

WHAT reasoning is, can be understood only by a man who has reasoned, and who is capable of reflecting upon this operation of his own mind. We can define it only by synonymous words or phrases, such as inferring, drawing a conclusion, and the like. The very notion of reasoning, therefore, can enter into the

mind by no other channel than that of reflecting upon the operation of reasoning in our own minds; and the notions of premises and conclusion, of a syllogism and all its constituent parts, of demonstration, and many others, have the same origin.

In all reasoning there must be a proposition inferred, and one or more from which it is inferred. And this power of inferring, or drawing a conclusion, is only another name for reasoning; the proposition inferred being called the conclusion, and the proposition or propositions from which it is inferred, the premises.

Reasoning may consist of many steps; the first conclusion being a premise to a second, that to a third, and so on, till we come to the last conclusion.

In a train of reasoning, the evidence of every step, where nothing is left to be supplied by the reader or hearer, must be immediately discernible by every man of ripe understanding, who has a distinct comprehension of the premises and conclusion, and who compares them together. To be able to comprehend, in one view, a combination of steps of this kind, is difficult, but the power of doing it may be much improved by habit.

In every chain of reasoning, the evidence of the

last conclusion can be no greater than that of the weakest link of the chain, whatever may be the strength of the rest.

The most remarkable distinction of reasonings is, that some are probable, others demonstrative.

In every step of demonstrative reasoning the inference is necessary; and we perceive it to be impossible, that the conclusion should not follow from the premises. In probable reasoning the connexion between the premises and the conclusion, is not necessary; nor do we perceive it to be impossible, that the first should be true whilst the last is false.

Hence demonstrative reasoning has no degrees, nor can one demonstration be stronger than another, though, in relation to our faculties, one may be more easily comprehended than another. Every demonstration gives equal strength to the conclusion, and leaves no possibility of its being false. Therefore, one demonstration clearly comprehended, gives all the evidence we are capable of receiving.

Demonstrative reasoning is applicable to necessary truth; probable reasoning to contingent. The strength of probable reasoning, for the most part, depends, not upon any one argument, but upon many, which unite their force and lead to the same con

clusion. Any one of them, by itself, would be insufficient to convince; but the whole, taken together, may have a force that is irresistible.

All reasoning, as before observed, must be grounded on truths that are known without reasoning. In every branch of real knowledge, there must be first principles, which are not grounded on reasoning, but all reasoning is grounded upon them. It has been shewn, that there are first principles of necessary truths, and first principles of contingent truths. Demonstrative reasoning is grounded upon the former, and probable reasoning upon the latter. Demonstrative evidence has no degrees; but probable evidence admits of all degrees from the least to the greatest; the greatest is called certainty.

Every degree of evidence perceived by the mind, produces a proportional degree of assent or belief. The judgment may be in perfect suspence between two contradictory opinions, when there is no evidence for either, or equal evidence for both. The least preponderancy on one side, inclines the judgment in proportion. Belief is mixed with doubt, more or less, until we come to the highest degree of evidence, when all doubt vanishes and the belief is firm and immovable.

Probable evidence not only differs in kind from

demonstrative, but is itself of different kinds. The chief of these are the following.

First, Human testimony, upon which the greatest part of human knowledge is built.

Second, The authority of those who are good judges of the point in question.

Third, That evidence by which we recognize the identity of things, and persons of our acquaintance.

Fourth, That which we have of men's future actions and conduct, from the general principles of action in man, or from our knowledge of the individual.

Fifth, That kind of probable evidence by which we collect men's characters and designs from their actions, speech, and other external signs.

Sixth, That which is called the calculation or probability of chances.

Seventh, That by which the known laws of nature have been discovered, and the effects which were produced by them in former ages, or which may be expected from them in time to come.

Besides the distinctions that have been already mentioned with regard to reasoning, it may be considered as hypothetical or inductive. The hypothetical reasoner who would account for of the appearances of nature, puts various propositions by way of supposition, and reasoning from these, endeavours

any