Argument, is not, indeed employed by all in the same sense; it would however generally be understood to ex tend to any argument drawn from an antecedent or fore runner, whether a Cause or not; e. g. "the mercury sinks, therefore it will rain." Now this Argument being drawn from a circumstance which, though an antecedent, is in no sense a Cause, would fall not under the former, but the latter, of the classes laid down; since when rain comes, no one would account for the phenomenon by the falling of the mercury; which they would call a Sign of rain; and yet most, perhaps, would class this among "a priori" Arguments. In like manner the expression, "a posteriori " Arguments, would not in its ordinary use coincide precisely, though it would very nearly, with the second class of Arguments. The division however which has here been adopted, appears to be both more philosophical, and also more precise, and conse

the sake of brevity, have found it useful to adopt, in drawing up an outline or analysis of any composition, certain arbitrary symbols, to denote, respectively, each class of Arguments and of Propositions; viz. A, for the former of the two classes of Aguments just described, (to denote "A priori," or "Antecedent," probability,) and B, for the lat ter, which, as consisting of several different kinds, may be denominated "the Body of evidence." Again, they designate the proposition, which accounts for the principal and original assertion, by a small "a," or Greek α, to denote its identity in substance with the Argument bearing the symbol “A,” though employed for a different purpose; viz. not to establish a fact that is doubtful, but to account for one that is admitted. The proposition, again, which results as a Consequence or Corollary from the principal one, they designate by the symbol C. There seems to be the same convenience in the use of these symbols as Logicians have found in the employmen* of A, E, I, O, to represent the four kinds of Propositions according to quantity and quality.

quently more practically useful, than any other; since there is so easy and decisive a test by which an Argument may be at once referred to the one or to the other of the classes described.

$ 3.

The second, then, of these classes, (viz. "Arguments which could not be used to account for the fact in question, supposing it granted,'') may be subdivided into two kinds; which will be designated by the terms "Sign and "Example."

Sign.

By "Sign," (so called from the nuɛtov of Aristotle,) is meant a species of Argument of which the analysis is as follows; As far as any circumstance is, what may be called, a Condition of the existence of a certain effect or phenomenon, so far it may be inferred from the existence of that Effect: if it be a Condition absolutely essential, the Argument is, of course, demonstrative; and the Probability is the stronger in proportion as we approach to that case.

Of this kind is the Argument in the instance lately given: a man is suspected as the perpetrator of the supposed murder, from the circumstance of his clothes being bloody; the murder being considered as in a certain degree a probable condition of that appearance; i. e. it is presumed that his clothes would not otherwise have been bloody. Again, from the appearance of ice, we infer, decidedly, the existence of a temperature not above freezing point, that temperature being an essen tial Condition of the crystallization of water.

Proof of a cause.

Among the circumstances which are conditional to any Effect, must evidently come

the Cause or Causes; and if there be only one possible Cause, this being absolutely essential, may be demonstratively proved from the Effect: if the same Effect might result from other Causes, then the Argument is, at best, but probable. But it is to be bserved, that there are also many circumstances which have no tendency to produce a certain Effect, though it cannot exist without them, and from which Effect, consequently, they may be inferred, as Conditions, though not Causes; e. g. a nian's "being alive one day," is a circumstance necessary, as a Condition, to his "dying the next;" but has no tendency to produce it; his having been alive, therefore, on the former day, may be proved from his subsequent death, but not vice versâ.*

It is to be observed therefore, that though it is very common for the Cause to be proved from its Effect, it is never so proved, so far forth as [] it is a Cause, but so far forth as it is a condition, or necessary circum

stance.

A Cause, again, may be employed to prove an Effect, (this being the first class of Arguments already described,) so far as it has a tendency to produce the Effect, even though it be not at all necessary to it; (i. e. when

* It is however very common, in the carelessness of ordinary language to mention, as the Causes of phenomena, circumstances which every one would allow, on consideration, to be not Causes, but only conditions of the Effects in question; e. g. it would be said of a tender plant, that it was destroyed in consequence of not being covered with a mat; though every one would mean to imply that the frost destroyed it; this being a Cause too well known to need being mentioned; and that which is spoken of as the Cause, viz the absence of a covering, being only the Condition, without which the real Cause could not have operated.

other Causes may produce the same Effect;) and inthis case, though the Effect may be inferred from the Cause, the Cause cannot be inferred from the Effect; e. g. from a mortal wound you may infer death, but not vice versa.

Logical and physical se

Lastly, when a Cause is also a necessary or probable condition, i. e. when it is the only possible or only likely Cause, then we may argue both ways; e. g. we may infer a General's success from his known skill, or, his skill from his known success: these two Arguments belonging, respectively, to the two classes originally laid down. And it is to be observed, that, in such Arguments from Sign as this last, the concluquence. sion which follows, logically, from the premiss, being the Cause from which the premiss follows, physically, (i. e. as a natural Effect,) there are in this case two different kinds of Sequence opposed to each other; e. g. "With many of them God was not wellpleased; for they were overthrown in the wilderness." In Arguments of the first class, on the contrary, these two kinds of Sequence are combined; i. e. the Conclusion which follows logically from the premiss, is also the Effect following physically from it as a Cause; a General's skill, e. g. being both the Cause and the Proof of his being likely to succeed.

It is most important to keep in mind the distinction wetween these two kinds of Sequence, which are, in Argument, sometimes combined, and sometimes opposed. There is no more fruitful source of confusion of thought than that ambiguity of the language employed on these subjects, which tends to confound together these two things, so entirely distinct in their nature. There is

hardly any argumentative writer on subjects involving a discussion of the Causes or Effects of any thing, who has clearly perceived and steadily kept in view the distinction I have been speaking of, or who has escaped the errors and perplexities thence resulting. The wide extent accordingly, and the importance of the mistakes and difficulties arising out of the ambiguity complained of, is incalculable. To dilate upon this point as fully as might be done with advantage, would exceed my present limits; but it will not be irrelevant to offer some remarks on the origin of the ambiguity complained of, and on the cautions to be used in guarding against being misled by it.

The premiss by which any thing is proved, is not necessarily the Cause of the fact's being such Logical seas it is; but it is the Cause of our knowing quence. or being convinced that it is so; e. g. the wetness of the earth is not the Cause of rain, but it is the Cause of our knowing that it has rained. These two things, the premiss which produces our conviction, and the Cause which produces that of which we are convinced, are the more likely to be confounded together, in the looseness of colloquial language, from the circumstance that (as has been above remarked) they frequently coincide; as, e. g. when we infer that the ground will be wet, from the fall of rain which produces that wetness. And hence it is that the same words have come to be applied, in common, to each kind of Sequence; e. g. an Effect is said to "follow" from a Cause, and a Conclusion to "follow" from the Premises; the words "Cause" and "Reason," are each applied indifferently, both to a Cause, properly so called, and to the premiss of an Ar