CAUSATION or Causality (Lat. causa, derived perhaps from the root cav-, as in caveo, and meaning something taken care of; corresponding to Gr. atria), a philosophical term for the operation of causes and for the mental conception of cause as operative throughout the universe. The word "cause" is correlative to "effect." Thus when one thing B is regarded as taking place in consequence of the action of another thing A, then A is said to be the cause of B, and B the effect of A. The philosophical problems connected with causation are both metaphysical and psychological. The metaphysical problem is part of the whole theory of existence. If everything is to be regarded as causally related with simultaneous and prior things or actions, it follows logically that the investigation of existence must, by hypothesis, be a regress to infinity, i.e. that we cannot conceive a beginning to existence. This explanation has led to the postulate of a First Cause, the nature of which is variously explained. The empirical school sees no difficulty in assuming a single event; but such a theory seems to deny the validity of the original hypothesis. Theologians assert a divine origin in the form of a personal selfexistent creator, while some metaphysical schools, preferring an impersonal First Cause, substitute the doctrine of the Absolute (q.v.). All the explanations are alike in this respect, that at a certain point they pass from the sphere of the senses, the physical world, to a metaphysical sphere in which the data and the intellectual operation of cognizing them are of a totally different quality. For example, the causal connexion between drunkenness and alcohol is not of the same observable character as that which is inferred between the infinite First Cause and the whole domain of sense-given phenomena.
A second metaphysical problem connected with causation arises when we consider the nature of necessity. It is generally assumed when two things are spoken of as cause and effect that their relation is a necessary one, or, in other words, that given the cause the effect must follow. The arguments connected with this problem belong to psychological discussions of causation. It is sufficient here to state that, in so far as causation is regarded as necessary connexion, it can form no part of a purely empirical theory of existence. The senses can say only that in all observed cases B has followed A, and this does not establish necessary connexion. The idea of causation is a purely intellectual (a priori) one.
The psychological problems connected with causation refer (I) to the origin of the conception in our minds; (2) to the validity of the conception. As regards the origin of the conception modern psychological analysis does not carry us beyond the doctrine of Locke contained in his chapter on "Power" (Essay, bk. ii. ch. 21), wherein he shows that the idea of power is got from the knowledge of our own activity. "Bodies by their causes," he says, "do not afford us so clear and distinct an idea of active power as we have from reflection on the operation of our minds." Putting Locke's doctrine into modern language, we may say that a man has the conception of cause primarily because he himself is a cause. The conception thus obtained we "project," that is, transfer to external objects, so far as we may find it useful to do so. Thus it is by a sort of analogy that we say that the sun is the "cause" of daylight. The rival theory to Locke's is that of Hume (Treatise, bk. i.), who derives the conception from the unaided operation of custom. When one object, A, has been noticed frequently to precede another object, B, an association between A and B is generated; and by virtue of this association, according to Hume, we say that A is the cause of B. The weakness of this account is that many invariable successions, such as day and night, do not make us regard the earlier members of the successions as causing the later; while in numberless cases w6 assert a causal connexion between two objects from a single experience of them.
We may proceed now to consider the validity of the conception of causation, which has been attacked from two sides. From the side of absolute idealism it is argued that the conception of cause, as involving a transition in time, cannot be ultimately valid, since the time-relation is not ultimately real. Upon this view (ably stated in Professor Bosanquet's Logic, bk. i. ch. 6) the more we know of causes and effects the less relevant becomes the time-relation and the nearer does the conception of cause and effect approach to another conception which is truly valid, the conception of ground and consequence. This means that, viewed from the standpoint of science, a draught of alcohol causes intoxication in no other sense than the triangularity of a triangle causes the interior angles to be equal to two right angles. This argument ceases to have cogency so soon as we deny its fundamental proposition that the time-relation is not ultimately real, but is irrelevant from the standpoint of science. This is a sheer assertion, contrary to all ordinary experience, which we have as much right to deny as the absolute idealists to affirm. It is only plausible to those who are committed to the Hegelian view of reality as consisting of a static system of universals, a view which has long been discredited in Germany, its native land, and is fast losing ground in England. Against the Hegelians we must maintain that the common distinction between "ground" and "cause" is perfectly justifiable. Whereas "ground" is an appropriate term for the relations within a static, simultaneous system, "cause" is appropriate to the relations within a dynamic, successive system.
From the other side the validity of causation has been attacked in the interests of the naturalism of the mechanical sciences. J. S. Mill argues that, scientifically, the cause of anything is the total assemblage of the conditions that precede its appearance, and that we have no right to give the name of cause to one of them exclusively of the others. The answer to this is that Mill fails to recognize that cause is a conception which we find useful in our dealings with nature, and that whatever conceptions we find useful we are justified in using. Among the conditions of an event there are always one or two that stand in specially close relation to it from our point of view; e.g. the draught of alcoholic liquor is more closely related to the man's drunkenness than is the attraction of the earth's gravity, though that also must co-operate in producing the effect. Such closely related conditions we find it convenient to single out by a term which expresses their analogy to the cause of causes, human volition.
These are the questions respecting causation which are matters of present controversy; there are in addition many other points which belong to the controversies of the past. Among the most important are Aristotle's classification of causes into material, formal, efficient and final, set forth in his Physics and elsewhere, and known as his doctrine of the Four Causes; Geulincx's Occasional Causes, meant as a solution of certain difficulties in the cosmology of Descartes; Leibnitz's law of Sufficient Reason; and Kant's explanation of cause and effect as an a priori category of the understanding, intended as an answer to Hume's scepticism, but very much less effective than the line of explanation suggested by Locke.
The following is a list of the various technical terms connected with causation which have been distinguished by logicians and psychologists.
The four Aristotelian causes are: (1) Material cause (LXrt), the material out of which a thing is made; the material cause of a house is the bricks and mortar of which it is composed. (2) Formal cause (Ei&os, Xayos, TO TL 17v Eivat), the general external appearance, shape, form of a thing; the formal cause of a triangle is its triangularity. (3) Efficient cause (apx77 Tris KL1/'7UEWS), the alcohol which makes a man drunk, the pistolbullet which kills. This is the cause as generally understood in modern usage. (4) Final cause (r Xos, To of g v€Ka), the object for which an action is done or a thing produced; the final cause of a commercial man's enterprise is to make his livelihood (see Teleology). This last cause was rejected by Bacon, Descartes and Spinoza, and indeed in ordinary usage the cause of an action in relation to its effect 3 the desire for, and expectation of, that effect on the part of the agent, not the effect itself. The Proximate cause of a phenomenon is the immediate or superficial as opposed to the Remote or Primary cause. Plurality of Causes is the much criticized doctrine of J. S. Mill that a fact may be the uniform consequent of several different antecedents. Causa essendi means the cause whereby a change is what it is, as opposed to the causa cognoscendi, the cause of our knowledge of the event; the two causes evidently need not be the same. An object is called causa immanens when it produces its changes by its own activity; a causa transiens produces changes in some other object. Causa sui is a term applied to God by Spinoza to denote that he is dependent on nothing and has no need of any external thing for his existence. Vera causa is a term used by Newton in his Principia, where he says, "No more causes of natural things are to be admitted than such as are both true and sufficient to explain the phenomena of those things"; verge causae must be such as we have good inductive grounds to believe do exist in nature, and do perform a part in phenomena analogous to those we would render an account of.