thing in actual operation. We can even say, in one very literal sense, that nothing is possible but what is actual; for only that which actually exists, can exist in actual compatibility with other things. The possibility of a thing which does not exist, and which is only conceived to exist, is only a conceived-of possibility.

We think very frequently of this merely ideal possibility, and much more frequently of it than we do of that actual possibility which the ideal would become if the object really existed. In this way we come to suppose that the assertion of possibility necessarily involves the non-existence of the thing possible. But that assertion, considered purely and in itself, does not involve a belief either in the existence or in the non-existence of its subject. That it does not, is evident, because the conviction of possibility is often cherished with the hope that it may add to itself the perception of fact. Those who went lately in search of the Arctic explorers did so in the hope, "They may be yet alive."

Real and hypothetical

In connection with the statement that possibility may be either actual or ideal, the possibility of a fact or possibility. the possibility of a thing supposed, - we must mark a very peculiar distinction of possibility into the real and the hypothetical. One might suppose real and hypothetical possibility to be the same as the actual and the ideal possibility just mentioned. The words naturally bear this signification; but in point of fact they are used in another sense. A thing is called really possible when any of its conditions are real and known to exist, even though the thing itself does not exist; and it is hypothetically possible when any of its conditions, being either non-existent or not known to exist, are yet supposed to be.

These modes of possibility are consistent both with each other and with actual impossibility. Had a man plenty of money to buy a farm, which the owner nevertheless could not be induced to sell at any price, the purchase would be really possible so far as regards money, and hypothetically possible so far as regards the consent of the owner, yet, on the whole, actually impossible. We do not commonly, however, while asserting real possibility, know that the object under consideration is, on the whole, impossible; nor do we always understand that the condition supposed in hypothetical possibility is non-existent: we frequently do know that it does not exist, but sometimes only do not know whether it exists or not. If the searchers for the Arctic explorers did not know, or have good reason to believe, that the explorers had food sufficient to support them for a given time, the hope of finding them alive would be supported by a possibility only abstract and hypothetical; yet this possibility of a sufficiency of food would consist with the fact of a sufficiency.

Partial and

Again, philosophy requires that we should discriminate perfected between partial and perfected possibility. A thing may be possibility known or supposed to be possible with reference to all the necessary conditions of its existence or with reference to some only; in this latter case it may be said to be partially, and in the former to be perfectly, possible. Partial possibility consists with either necessity or impossibility; but perfected possibility involves necessity, and excludes

Logical dis

impossibility. For example, if a person had ability, opportunity, preparation, and sufficient inducement to make a speech, in short, all the conditions of this effect, the speech would be both possible and necessary. But if only one or two conditions were known or supposed to exist, and it were left unsettled whether or not the others existed or could exist, then the speech would be possible so far as concerned the known or posited conditions, but, on the whole, it might be either necessary or impossible. So far as a thing is possible, it is compatible with other things; so far as it is necessary, it is inseparably coherent with other things. These are different, though they are intimately allied relations. Another needful distinction is that between possibility tinguished in general, or logical possibility (or compossibility, as Chilfrom causal lingworth named it), and causal possibility. This is exactly possibility. parallel to the distinction, already discussed, between causal and logical necessity. A thing is causally possible when any of its causal conditions does or may exist. Power, adequate in nature and degree to the production of the object, is the most important of these conditions. When we find that an adequate power exists, we say that the thing is possible so far as that condition is concerned. Then we inquire concerning other conditions, and from their existence or nonexistence determine the question as to the remaining elements of a complete possibility. If there were a tailor, we would know that a coat was possible so far as regards productive skill. We might then ask, Is it possible as regards material? Where are the cloth, lining, thread, buttons, and so forth? Next, Is it possible as to instruments? Has the man a workshop, needles, scissors, and other implements? Finally, Is it possible as to sufficient inducement? Have you the money to pay the tailor for the coat? Thus one might successively consider the different causal conditions of a coat, so far as there was any question concerning each; and he would naturally do so in the order of their practical importance.

A man

On the other hand, a thing is logically possible when any of its necessary conditions exist, whether they be causal conditions or not. ignorant of the details of Japanese geography might say, Yokohama and Yeddo may be twenty, or they may be one hundred, miles apart, for all that I know: " because either of these supposed things would be compatible with the fact that both cities are in Japan; either of them would be possible with reference simply to space relations.

a

Only effects are causally possible; causes, as such, are possible logically, not causally. God is neither causally possible nor causally necessary, he never could have been produced, but he is logically possible and logically necessary. His existence is both compatible with that of the universe, and necessary as that of the cause of the universe, cause that must have existed. The reasonings of pure mathematics refer to logical but not to causal possibility and necessity. The thoughts of daily life and of scientific experiment are chiefly concerned with causal. These thoughts, too, greatly influence our ordinary use of language. Hence the possible often signifies that which can be produced or brought about; indeed, originally the possible may have been the practicable or the makable. But possibility in general

is simply the existential compatibility of a thing, and its conditions, with given circumstances, and is not at all confined to the compatibility of the production of a thing with given circumstances.

subservient

Five steps.

Reasoning in 3. We are now prepared to understand how the mind, in its possibility is pursuit of the cognition of fact, which alone is true and to reasoning complete cognition, forms and uses its knowledge of the in necessity, possible. One is often unable to determine directly, from his knowledge of the circumstances of a case, what the truth may be respecting some point of inquiry, - that is, he is unable to discover any real antecedent which, as involving a logical condition, necessitates the reality of some object conceived of. Such antecedents may exist, but he knows not where to seek for them, or, at least, has not been able to find any. In these circumstances the direct search for truth is abandoned, and the inquiry, Is the thing supposed possible? takes the place of the question, Is it necessary?

This inquiry as to possibility may be prosecuted in various ways; but when fully developed it is twofold, referring, first, to hypothetical, and then to real, possibility.

For first, if need be, we ask as to the abstract possibility of the thing, that is, its possibility without reference either to any specific circumstances or to the actual existence or non-existence of any conditions. This inquiry is to determine the ideal compossibility of the conditions, internal and external, of the object with each other, and with the necessary elements and laws of being. If any conditions be found incompatible with each other, or with any radical law of existence, there is no need of further inquiry. No matter what existing circumstances may be, the thing is impossible, and does not exist.

But if the abstract supposition do not thus involve contradiction and absurdity, our next inquiry might concern the hypothetical possibility of the thing under the given circumstances. In other words, we might ask whether the necessary conditions of the thing be possible and supposable in the case presented. Here, also, if any condition should appear thus impossible, our quest for truth would terminate.

Otherwise we should immediately pass to the second leading inquiry concerning possibility, and should ask, Is the thing really possible? Do its conditions really exist? For we assume that an attentive study of the thing under consideration has brought distinctly to view its necessary parts and other conditions. Suppose now we find that some condition of the thing does not exist, is not contained in the given circumstances. This being the case, the thing is really impossible; for a thing cannot exist so long as any one of its conditions is nonexistent. Thus, again, the possible has been our guide to the real; it has led again to the really non-existent.

But suppose, further, that every condition concerning which we can inquire is found to be a reality. We now say that, so far as we can see, the thing is really possible, and cannot be denied to exist; we can inferentially deny only the impossible. In this case reasoning in possibility enables one to reject any unfounded disbelief, that is, any unfounded belief in the non-existence of the object, and prepares the mind for the proper consideration of evidence.

Moreover, logical conditions, or exact antecedents, being composed

of necessary conditions, inquiry after the latter puts us better in the way of meeting with the former, or with reasons containing them; and thus, searching within and over the field of necessary conditions, we are in the way of finding conclusive antecedents, if such are discoverable.

Finally, therefore, suppose that certain conditions are found to be real, which, taken together, can belong to but one object, and that the object whose reality is in question. The inference of possibility is now replaced by the inference of fact; our inquiry terminates in the assertion of positive reality. Thus, in several ways and degrees, reasoning in possibility subserves reasoning in necessity.

The ordinary inference of the possible is concerned, almost exclusively, with real possibility and real conditions. The abstract possibility of a thing is generally known before the commencement of inquiry; and that hypothetical possibility which is limited by the given circumstances serves only to direct our search after real conditions. Those who set out to rescue the Arctic explorers had no doubt that men could exist anywhere under certain conditions; nor had they any difficulty in imagining that their long-absent countrymen might still live under those conditions, even in the most frozen and inhospitable latitudes. But their hopes and their search were based on the belief that some of those conditious were, or had been, actual, and that others might be found to exist. They knew that the expedition had been sent out in strong and well-equipped vessels, with abundant provision of clothing, food, and fuel, and with the means of obtaining such supplies as those hyperborean regions afforded. These facts were the basis of a real possibility. Still the questions were unsettled whether the ships had proved of sufficient strength, whether provisions had not been exhausted, and whether the adventurers had succeeded in procuring additional supplies. Let us suppose, now, that the rescuing party, in their progress, should obtain, from natives or from deposited records, evidence as to one and another of these doubtful points. Plainly their hope would be confirmed, the possibility of timely relief would become more real; it would be based on a greater number of real conditions. Finally, should they ascertain that the explorers had been lately seen, and that they had the necessary means of living for a certain time, they would press forward in the full confidence of finding them.

Inference of 4. The explanations above given describe only the inferthe possible ence of that which we ordinarily mean by the possible. Comnot to be. monly the possible means the possible to be, just as the impossible commonly signifies the impossible to be. Sometimes, however, we speak of the possible not to be, of that whose non-existence is or would be compatible with given circumstances; and our reasoning concerning this possible has a law of its own. A thing is inferred as possible to be when its conditions, so far as considered, exist or are possible; but it is inferred as possible not to be when its conditions, so far as found existent or possible, do not constitute a logical condition. This is the law of the possibility not to be, real and hypothetical.

We see, therefore, how reasoning in possibility (whether positive or negative possibility) is closely related to reasoning in necessity

(whether positive or negative). Both modes of inference are based on the radical principle that all things exist as conditioned. Both arise from the consideration of things as conditioned; both even have a reference to logical conditions. The necessary to be is inferred directly from the existence of such a condition. The impossible, or necessary not to be, is inferred from the non-existence of one or more of those necessary conditions out of which every logical condition is constituted. The possible to be is inferred from the existence of necessary conditions when we can at the same time suppose the existence of a logical condition containing them. And the possible not to be is inferred from the existence of necessary conditions when we can suppose the non-existence of the logical condition of which they would be parts. These remarks show how the possible to be leads towards the necessary, and how the possible not to be leads towards the impossible.

Intermedi

CHAPTER XXII.

CONTINGENCY AND PROBABILITY.

1. THE only definition of possibility which seems to ate possibil cover every case is that which makes it the existential ity defined. compatibility of one thing with others. When the existence of a thing, so far as relates to any of its necessary conditions, is compatible with given circumstances, we have the possible to be; and when its non-existence, notwithstanding the existence of some conditions, is compatible with given circumstances, we have the possible not to be. When all the necessary conditions of a thing exist, it is both perfectly possible to be and necessary to be; and when any of these conditions do not exist, it is both perfectly possible not to be and impossible to be. But when some of the conditions exist, and we have no reason to believe the others existent or to believe them nonexistent, we say that the thing is possible either to be or not to be. This, too, is the possibility most frequently considered.

When possibility has this double character it may be called intermediate, as lying between those possibilities, positive and negative, which belong to facts, and which consist with necessity and impossibility. This intermediate possibility is of the same nature with that already described as partial, excepting only that it has a doubleness, and looks in two directions.

The above statements, for the sake of simplicity, directly refer only to real possibility, in which conditions are not merely supposed, but asserted to exist. Similar statements might be made in regard to hypothetical possibility; which, however, we need not specifically discuss.

defined.

Intermediate possibility is the primary basis or ground Contingency for judgments of probability; and when it is thought of as such, it is styled contingency. For it could not be probable that there will be frost in Clinton on the 4th of March, were it not possible both that there should be and that there should not be frost