Some writers have observed that the causal conjunctions are employed to denote respectively cause and effbet, as well as premiss and conclusion ; as in the following examples :—"This ground is rich because the trees on it are flourishing;" or, "the trees are flourishing, and therefore the soil must be rich ;" where the conjunctions because and therefore are considered to be used to denote the connection of pre miss and conclusion. But in the following sentences, "the trees flourish because the ground is rich ;" or "the ground is rich, and therefore the trees flourish ;" the same conjunctions, it Is said, are 114 to denote the connection of cause and effect ; and it is aided that in the latter case "the luxuriance of the trees, being evident to the eye, would hardly need to be proved, but might need to be accounted for;" and as to the former case, it is remarked, "that the luxuriauco of the trees is not the cause of the soil's fertility, but only the cause of my knowing it." Now in the expression," the trees are flourishing, and therefore the soil mast be rich" (if for mast be we write is, which ought to be done), it may be meant to affirm, either that the trt•es are (lottrishing, mud that the quality of the soil is unknown ; or it may be meant that the trees are flourishing, and that the soil also is rich. In the former caw the richness of the soil is concluded, according to the collusion expres sion, from the suppressed premiss of the invariable coincidence of flourishing trees and rich soil, and as the world knows or says (which for the present purpose is the same thing) that a rich soil is necessary in order that trees may flourish, the richness of the soil is in fact, according to the common notion of cause and effect, here also con sidered to be the cause of the luxuriance of the trees, if we look to the matter of the syllogism. In the latter case, if both things are affirmed, both that the trees flourish and that the soil is rich, the same thing is affirmed as in the sentence," the ground is rich and therefore the trees flourish ;" and in both these cases, when the two propositions are con sidered as affirmations, not connected in the way of conclusion, nothing more is effected by the word therefore than to suggest the notion of the invariable coincidence of flourishing trees and rich soil.
The Conclusion of the "ground being rich because the trees on it are flourishing" (the richness of the ground in question not being known otherwise than by the trees) cannot be made except from the premiss, " wherever trees flourish, there the ground is rich." Now though It may be true that " wherever trees flourish, there the ground is rich," It may not be true that " wherever the ground is rich, there trees flourish," for the ground may be rich, and covered with water in which trees will not flourish. But if we Affirm that " the trees flourish because the ground is rich," we affirm both " that the trees flourish" and "that the ground is rich," which again is nothing more than affirming by implication that " wherever trees flourish, there the ground is rich," leaving it, as before, possible that there may be rich ground where trees do not ( for some reason or other) flourish.
Now it is said that in the former case, where a Conclusion is made, the luxuriance of the trees is considered to be the cause of my knowing the fertility of the sail ; that is, in the conclusion, " the ground is rich because the trees on it are flourishing ;" " the ground is rich" is my (concluded) knowledge, and because is there used to express cause and effect, as between "flourishing trees" and " my knowledge." In the latter case, where both propositions are affirmative, but neither of them in the way of conclusion, it is said that the luxuriance of the trees does not require proof, but requires to be accounted for • that is, richness of soil and luxuriance are here considered in the relation of cause and effect. According to this, a relation of cause and effect, though not of the same cause and effect, is indicated in both cases by the word because : and in the former case the richness of the soil is considered to be peered also.
This is rather perplexing, but perhaps the perplexity may be got rid of thus The ground is rich because the trees on it are flourishing," is necessarily true, if it is also true that "wherever trees flourish, there the ground is rich ;" but this general proposition must be proved in some way or assumed, in order that the logical conclusion may also be a true conclusion. "The trees flourish, because the ground is rich :" hero both facts are prored or assumed (which for the present purpose is the same thing), and it is also affirmed by implication that " wherever trees flourish, there the ground is rich." The difference between the two sentences then is this :—the former affirms that a particular soil is rich, if soil is always rich under similar circum stances; and the reduction of the expression to the complete syllogis tic form shows us what must be proved or assumed in order that the conclusion shall be true in this particular case. The latter affirms the particular thing to be true, which in the former is only true upon a certain condition ; and it also affirms by implication the truth of this certain condition. The former is a syllogism, because that which is said of the whole may be said of a part. The latter is nothing more than the implicit statement of a general proposition contained in the explicit statement of a particular instance : it is no logical inference ; it is no logical induction ; it is simply a statement of a thing being true in a certain case, with an implicit, assertion that the same thing is true in all similar cases; in other words, the form of language Implicitly contains the affirmation of a general proposition, which can only be the result of an induction in the non-logical souse of that • term.
The difference between logical Deduction and Induction is explained in the article best-rms. But it will not be out of place to say a few words on the subject here. In the Deductive Syllogism, we proceed from the whole to its parts, from the thing containing to the things or some of the things contained ; and this is true notwithstanding it is not so expressed in the common form of language. For the particular conclusion, as already observed, is the thing which in ordinary language is said to be proved; but there is no demonstrative evidence to the mind, except it is shown that the particular conclusion is contained in a general proposition. The deductive syllogism as already explained shows what this general proposition is, and this general proposition is mutinied to be true, or is known to be true in some other way (by induction, properly so called, for instance) than by means of the syllogisms. But there is another mode of operation by which the mind can proceed from particulars to generals ; but this, which may be called the Inductive Syllogism, is no syllogism, that is, no necessary conclusion, unless all the particulars are enumerated, or assumed to be enumerated ; and in this consists the difference between the Inductive Syllogism and Induction, or wlmt is sometimes, but, we think, not with strict propriety, called Inductive Iteasening, which however is no operation of reason, but one of the understanding only ; or, to prevent disputes about terms, it is not the same mental process as that of the Logical Induction, for its conclusion is not necessary. Tide Induc tion then, which limas um from the observation of ono or more like facts to make a general assertion which will comprehend like facts not observed, is a material illation of quite a different character (from the other. This process has sometimes been absurdly considered as a peculiar discovery of modern times, though it must have been practised by the first man who ever made use of his eyes. The process of investigating and collecting facts which aro among the phenomena of the material world, has been greatly improved in modern times.