It does not involve necessary determination.
Now it is obvious that the relation of causality, understood in this second way, does not involve the necessary determination of the effect by the cause. History indeed proves it. We see ancient hylozoism, the first outcome of this conception of causality, explained the regular succession of causes and effects by a real deus ex machina: sometimes it was a Necessity external to things and hovering over them, sometimes an inner Reason acting by rules somewhat similar to those which govern our own conduct. Nor do the perceptions of Leibniz's monad necessitate one another; God has to regulate their order in advance. In fact, Leibniz's determinism does not spring from his conception of the monad, but from the fact that he builds up the universe with monads only. Having denied all mechanical influence of substances on one another, he had to explain how it happens that their states correspond. Hence a determinism which arises from the necessity of positing a pre-established harmony, and not at all from the dynamic conception of the relation of causality. But let us leave history aside. Consciousness itself testifies that the abstract idea of force is that of indeterminate effort, that of an effort which has not yet issued in an act and in which the act is still only at the stage of an idea. In other words, the dynamic conception of the causal relation ascribes to things a duration absolutely like our own, whatever may be the nature of this duration; to picture in this way the relation of cause to effect is to assume that the future is not more closely bound up with the present in the external world than it is in our own inner life.
Each of these contradictory interpretations of causality and duration by itself safeguards freedom; taken together they destroy it.
It follows from this twofold analysis that the principle of causality involves two contradictory conceptions of duration, two mutually exclusive ways of prefiguring the future in the present. Sometimes all phenomena, physical or psychical, are pictured as enduring in the same way, and therefore in the way that we do: in this case the future will exist in the present only as an idea, and the passing from the present to the future will take the form of an effort which does not always lead to the realization of the idea conceived. Sometimes, on the other hand, duration is regarded as the characteristic form of conscious states; in this case, things are no longer supposed to endure as we do, and a mathematical pre-existence of their future in their present is admitted. Now, each of these two hypotheses, when taken by itself, safeguards human freedom; for the first would lead to the result that even the phenomena of nature were contingent, and the second, by attributing the necessary determination of physical phenomena to the fact that things do not endure as we do, invites us to regard the self which is subject to duration as a free force. Therefore, every clear conception of causality, where we know our own meaning, leads to the idea of human freedom as a natural consequence. Unfortunately, the habit has grown up of taking the principle of causality in both senses at the same time, because the one is more flattering to our imagination and the other is more favourable to mathematical reasoning. Sometimes we think particularly of the regular succession of physical phenomena and of the kind of inner effort by which one becomes another; sometimes we fix our mind on the absolute regularity of these phenomena, and from the idea of regularity we pass by imperceptible steps to that of mathematical necessity, which excludes duration understood in the first way. And we do not see any harm in letting these two conceptions blend into one another, and in assigning greater importance to the one or the other according as we are more or less concerned with the interests of science. But to apply the principle of causality, in this ambiguous form, to the succession of conscious states, is uselessly and wantonly to run into inextricable difficulties. The idea of force, which really excludes that of necessary determination, has got into the habit, so to speak, of amalgamating with that of necessity, in consequence of the very use which we make of the principle of causality in nature. On the one hand, we know force only through the witness of consciousness, and consciousness does not assert, does not even understand, the absolute determination, now, of actions that are still to come: that is all that experience teaches us, and if we hold by experience we should say that we feel ourselves free, that we perceive force, rightly or wrongly, as a free spontaneity. But, on the other hand, this idea of force, carried over into nature, travelling there side by side with the idea of necessity, has got corrupted before it returns from the journey. It returns impregnated with the idea of necessity: and in the light of the rôle which we have made it play in the external world, we regard force as determining with strict necessity the effects which flow from it. Here again the mistake made by consciousness arises from the fact that it looks at the self, not directly, but by a kind of refraction through the forms which it has lent to external perception, and which the latter does not give back without having left its mark on them. A compromise, as it were, has been brought about between the idea of force and that of necessary determination. The wholly mechanical determination of two external phenomena by one another now assumes in our eyes the same form as the dynamic relation of our exertion of force to the act which springs from it: but, in return, this latter relation takes the form of a mathematical derivation, the human action being supposed to issue mechanically, and therefore necessarily, from the force which produces it. There is no doubt that this mingling of two different and almost opposite ideas offers advantages to common sense, since it enables us to picture in the same way, and denote by one and the same word, both the relation which exists between two moments of our life and that which binds together the successive moments of the external world. We have seen that, though our deepest conscious states exclude numerical multiplicity, yet we break them up into parts external to one another; that though the elements of concrete duration permeate one another, duration expressing itself in extensity exhibits moments as distinct as the bodies scattered in space. Is it surprising, then, that between the moments of our life, when it has been, so to speak, objectified, we set up a relation analogous to the objective relation of causality, and that an exchange, which again may be compared to the phenomenon of endosmosis, takes place between the dynamic idea of free effort and the mathematical concept of necessary determination?
Though united in popular thought, the ideas of free effort and necessary determination are kept apart by physical science.
But the sundering of these two ideas is an accomplished fact in the natural sciences. The physicist may speak of forces, and even picture their mode of action by analogy with an inner effort, but he will never introduce this hypothesis into a scientific explanation. Even those who, with Faraday, replace the extended atoms by dynamic points, will treat the centres of force and the lines of force mathematically, without troubling about force itself considered as an activity or an effort. It thus comes to be understood that the relation of external causality is purely mathematical, and has no resemblance to the relation between psychical force and the act which springs from it.
They should be kept apart too by psychology.
It is now time to add that the relation of inner causality is purely dynamic, and has no analogy with the relation of two external phenomena which condition one another. For as the latter are capable of recurring in a homogeneous space, their relation can be expressed in terms of a law, whereas deep-seated psychic states occur once in consciousness and will never occur again. A careful analysis of the psychological phenomenon led us to this conclusion in the beginning: the study of the notions of causality and duration, viewed in themselves, has merely confirmed it.
Freedom real but indefineable.
We can now formulate our conception of freedom. Freedom is the relation of the concrete self to the act which it performs. This relation is indefinable, just because we are free. For we can analyse a thing, but not a process; we can break up extensity, but not duration. Or, if we persist in analysing it, we unconsciously transform the process into a thing and duration into extensity. By the very fact of breaking up concrete time we set out its moments in homogeneous space; in place of the doing we put the already done; and, as we have begun by, so to speak, stereotyping the activity of the self, we see spontaneity settle down into inertia and freedom into necessity. Thus, any positive definition of freedom will ensure the victory of determinism.