Any inquiry must begin from prima facie distinctions within its field of study and from the most general distinctions. It must start that is to say with a classification of its data. The principle of this classification must have a prima facie validity. By this is meant that there must be good reasons for adopting this rather than any other principle as our method of discrimination so far as our knowledge goes; although as the inquiry progresses we may have to discard it in favour of another. In a philosophical inquiry the field is unlimited; consequently we must start from a prima facie distinction of universal application. The distinction between ‘mental’ and ‘material’ is such a prima facie principle. We may formulate it thus: ‘Everything without exception is either material or mental and nothing can be both.’ We might call this a prima facie principle of metaphysical classification.

We have seen reason in reflecting upon the development of modern philosophy to discard this particular principle of classification. There are prima facie grounds for its adoption only from a merely theoretical standpoint. From the new point of view which we have adopted a new classificatory principle is needed. Now the new point of view being that of the Agent is practical; consequently the distinguishable elements in experience are activities not objects; while for primary awareness—for knowledge in action—they are changes. Now there is a prima facie distinction of unlimited application which we use for classifying changes. All changes we assume are either ‘acts’ or ‘events’; either they are ‘doings’ or they are ‘happenings’. Further this distinction between what is done and what happens is exclusive and exhaustive. Any change is either an event or an act and no change can be both. This then would seem to be the prima facie distinction of which we are in search.

It might seem that to substitute the distinction of ‘act’ and ‘event’ for the traditional distinction between ‘mind’ and ‘matter’ is merely to exchange one form of dualism for another. Now from a merely theoretical point of view this is indeed the case. As concepts ‘act’ and ‘event’ exclude one another. Indeed we have already seen that the mind-matter dualism is the theoretical reflection of the dualism between theory and practice. But what is a dualism from the theoretical point of view is not necessarily so from the practical. The experience of the Self as agent we have discovered requires for its representation a form in which a positive includes and is constituted by its own negative. Prima facie therefore what happens must be taken as the negative aspect of what is done. The ‘I do’ as the primary datum is positive: the ‘it happens’ must then be the included negative. One of the most familiar examples of this relation of ‘doing’ and ‘happening’ is the actual experience of thinking. Thinking is something that I do; yet when I think my thoughts appear to develop themselves in me in a necessary fashion; and any new discovery I make in thinking appears to happen of itself in ‘a flash of insight or inspiration’ which I must wait for and cannot command at will. I find myself saying ‘Suddenly the thought struck me’. Yet I am well aware that unless I had been thinking and indeed thinking hard and attentively the thought would not have struck me. This is not however a peculiarity of reflection. In all our actions there is included much that merely happens. If this were not so nothing could ever be done. When I decide to do anything the necessary co-ordination of nervous and muscular activities which the intention requires happens automatically and is included in the doing of what I intend.

Now ‘act’ and ‘event’ are practical concepts and the distinction between them is a practical distinction. From a purely theoretical point of view both are merely apprehended changes; perhaps changes in a visual field. A change is in itself as apprehended neither ‘act’ nor ‘event’. I mean by this that it is the mere substitution of one appearance for another. To call it either ‘act’ or ‘event’ is to refer beyond it to something else which ‘produces’ it. No inspection of a change however minute and careful will of itself determine whether it was ‘done’ or merely ‘happened’; indeed inspection cannot even suggest either of these concepts. In practice we sometimes find ourselves unable to decide whether a change is an event or an act. Is the noise of a door closing in the night due to a burglar in the house or just to the wind? The question can be settled only by further evidence. In a word to call anything either an event or an act is to refer beyond what is observed to an activity—an expenditure of energy—of which it is the product. Apart from such a practical reference it is neither the one nor the other. It is this fact which gives rise to the conception whether legitimate or not of pure contingency. A purely contingent occurrence would be an observed change which was neither an act nor an event; something that could not be referred beyond itself to a ‘source’ or ‘origin’; something for which nothing at all was responsible and which could not therefore be accounted for.

To call any apprehended change an ‘act’ is to refer it to an agent as its source. To call it an event is to refer it to a non-agent. We express the distinction between acts and events therefore if we say: for an event there is a cause; for an act there is a reason. If we believe a change to be an event and wish to understand it we must ask ‘What caused it?’; if we think it an act we have to ask ‘Who did it and why did he do it?’ The explanation of an event is the discovery of the cause which produced it; the explanation of an act is the discovery of the reason for its performance. The cause stands to the event as the reason stands to the act. But since to call an occurrence an event is to refer it to a cause; and to call it an act is to refer it to a reason we can formulate the general principles involved in two universal assertions. For every event there is a cause; for every act there is a reason. And since the distinction of ‘act’ and ‘event’ is a principle of ultimate or metaphysical classification and institutes a conceptual dualism we must recognize that the distinction between ‘reason’ and ‘cause’ is an absolute distinction; so that no act can have a cause; and no event a reason. At the same time we must remember that ‘act’ and ‘event’ are existential concepts. An imagined event is an event which does not occur; an imagined act even if the agent has decided to do it is an act which has not and may never take place. It is an obvious corollary of this that it is nonsensical to ask what is the cause of an act or the reason for an event. The assertion that every event has a cause does not contradict the assertion that no act has a cause; it implies this.

Though we are concerned here with the distinction of act and event only we should for the sake of completeness interpose a word or two about organic changes where there is ground for a distinction between the principle of cause and effect and the principle of stimulus and reaction. The difference lies as we noted already in this—that we understand the behaviour of organisms teleologically in terms of adaptation. We do not however assign a reason for the behaviour but only a motive. For even if consciousness enters into its determination this consciousness is motive and not cognitive. It is important for this reason to distinguish two senses in which the notion of teleology may be employed and which are often confused. In both cases we account for a process of change by reference to an end. In one case however the process is determined by a knowledge of the end while in the other knowledge is not a determinant of the process and even if present does not enter into our account of the process. In understanding organic behaviour teleologically our point of reference is the end actually or normally occurring as the final stage of the process. We determine the process as a series of successive changes necessary to reach this end. In understanding deliberate human behaviour teleologically on the other hand our point of reference is not the end actually reached but the end proposed to himself or intended by the agent and we understand the process of action as a successful or unsuccessful attempt to realize this intention which is the agent's reason for acting as he has acted. As a result of this we judge if he is successful that he has done the right thing; if unsuccessful that he has made a mistake or acted wrongly. These two types of process have therefore quite distinct logical forms. If we confuse them it is because of an ambiguity in the term ‘end’. As it is essential to avoid this confusion the term ‘teleology’ should be restricted to its original and proper use which lies in the description and comprehension of organic behaviour. Action is not teleological but intentional. It is described and understood by reference to the purpose of an agent.

If we make this distinction clearly organic behaviour is brought within the field of what happens in any prima facie distinction we draw between acts and events. If the limitation of teleological categories to the organic field seems to anyone to be merely a verbal device for avoiding awkward questions we must insist that this is not the case. For though some classes of acts are properly described and understood by reference to an end this is by no means true of all acts. It is possible only where the end is determinate before action begins and remains unmodified throughout the process of acting. The end of an action being matter of intention and not matter of fact is in principle indeterminate. It is not actual but determinable by the agent in action. The general who determined the movements of his troops in a battle before action was joined and who maintained his intention throughout the battle whatever the enemy did would deserve to lose the battle and almost certainly would. The inability to alter one's plans as a changing situation demands is a form of stupidity: the refusal to do so is the kind of practical stupidity which we call obstinacy or pig-headedness. In principle therefore action in general cannot be defined teleologically even if there is always a teleological element contained in it. It can be defined only as an activity informed by knowledge. Since time is the form of action this knowledge has a necessary reference to the future. The ‘I do’ is in any actual case an ‘I do x’. But to the question ‘What is x?’ that is ‘What are you doing?’ though some answer must be possible it is not necessarily a very determinate answer; and in principle can never be completely determinate but only to a greater or lesser degree. The agent can always change his mind. I may answer the question ‘What are you doing?’ by saying ‘I'm walking eastwards.’ If then the questioner says ‘Yes but where are you going?’ I may reply ‘I don't know yet; I haven't made up my mind.’ The reference to the future must be sufficient to determine a direction of advance; it need not determine an end. And since even the ends which we do determine in action are only relative since they are also starting-points of further action we always know to some extent and never know with full finality what we are doing.

We may now return to the conception of causality and consider its relation to action. Since the direction of action qua action is determined by the knowledge which is one of its dimensions it is understood by reference to this knowledge; that is to say by discovering the reason why the agent did it. If we know this reason fully then we understand the action fully. (The negative which must qualify this we shall consider presently.) This is the primary understanding we possess from which all other forms of the understanding of activity must be derived by limitation. An event therefore is a change which cannot be referred to an agent as its source. It is not directed by knowledge; consequently no reason can be given for it. The idea of an event is the idea of an action from which the element of knowledge has been excluded. The personal experience which is the necessary model for this is twofold. In the first place there are organic activities of our own which though teleological are yet ‘unconscious’ or automatic. These may or may not be accompanied by knowledge; but if they are the knowledge does not determine them and is not integrated with our own movements. Secondly there is our experience of ‘accidents’. Accidents though they form part of the observable process of our movements in action are not integrated with it and cannot be referred to any intention of ours. If for instance I accidentally drop and break a glass which I am carrying the breakage is produced by me yet is not an act of mine. The question ‘Why did you break that glass?’ has no answer and is inadmissible. I should reply ‘I didn't; it was a pure accident.’ Here is an occurrence in which I am implicated yet which cannot be referred to my intention as its source. We may notice here though it is not strictly relevant that this distinction between act and accident can never be determined by any inference from observed fact. The inference from fact to intention is always formally invalid. The evidence is always in principle circumstantial. Yet the conclusion may be certain for all that. The extra-logical element in any proof of intention is an analogy from our own experience as agents. Further even when we are convinced that there was no intention present we may still suspect an unconscious motive. If so the accident is to be understood teleologically as a phenomenon of motive consciousness as a case of organic causality. We must note however that such determination by unconscious motives is unintentional. There can be no such thing as an unconscious intention. The term ‘intention’ at least in a context like the present always implies knowledge determining action.

Now when no reason can be assigned for an observed change and it is therefore not an act we call it an ‘event’ and refer it to a ‘cause’. What then do we mean by a ‘cause’? We mean the source of an occurrence which stands to an event as an agent stands to his act but which is not an agent. Since in any attempt to understand events the conception of cause must be thought positively we must say that a cause is a source of occurrences which is a non-agent; an existent which is other than an agent.

The conception of ‘cause’ is inherently self-contradictory. It is the conception of an agent that is not an agent the negation of agency. The negative we know cannot exist independently but only as the negative aspect of a positive in the form of the personal. Within action which is a personal concept there not merely can but must be a negation of action; but this negation is in the last analysis a self-negation. If the negative aspect is thought as existing independently of the positive the result is a contradiction. We think the non-existent as existing. The difficulties of any theory of causation arise from this. The conception of cause both includes and excludes the idea of the ‘production’ of an effect. In consequence whatever we assign as the cause of an event is something which is not in itself capable of producing an effect but only as it were of transmitting it. It is a means through which something else produces the occurrence. In other words the ‘cause’ turns out to be merely another event which must be itself referred to another cause. An infinite regress of causes faces us in every case. This is what is meant when people say that a causal explanation only tells us how things happen and not why they happen; or better still that it describes the course of events without explaining it.

So long as the use of the notion of cause falls within action and so has a practical reference it is meaningful and indispensable. For in such cases it refers to a negative activity which falls within the positive activity of an actual agent. The case of ill-health or disease whether ‘mental’ or ‘organic’ is presumably the primary instance; for then the organic functioning of the body or its motive consciousness is clearly a negative aspect of action. But the same is true of tools instruments or machines which we construct for our use and which are means for the transmission of our own energy and so in a sense extensions of our own bodies. A breakdown in these as in our own organic functioning leads us to ask for its cause. The question is now a practical one and the term ‘cause’ refers to that which we must alter by our action in order to restore our capacity to act through the instrument.1

When however we are concerned with purely theoretical construction the contradiction is a mere source of embarrassment and scientific theory therefore seeks to replace it by a less objectionable notion from which the idea of ‘production’ is at least more remote. This is the idea of natural law. Instead of inquiring for the cause of an event we ask for a law in accordance with which it happens. This idea of a law of Nature is of course anthropomorphic in the bad sense of the term. A law is a general prescription which an agent issues for the actions of another agent; and since the other is an agent he can choose to disregard it. In all strictness no agent can compel another agent to do anything; he can at most provide what he hopes will prove a sufficient motive to determine the other agent's choice of the desired course of action. A law of Nature is said to be not prescriptive but merely descriptive. Strictly speaking it is not a law at all; but in calling it a law we are thinking of it as a prescription which in the nature of the case can never be disregarded. The idea of descriptive law is perhaps too well established to provoke serious misunderstanding in science. But its emotional effect is the more objectionable that it is unconscious; serving to maintain an attitude of misplaced reverence for Nature as the Lawgiver which echoes an ancient worship; and to invest the professional scientist with magical powers for the salvation of the world. The scientists of course make no such superstitious claims; yet they would be hardly human if they did not enjoy and even profit by the adulation of the vulgar. It is desirable that this atavism should be exorcised; for it would be a pity and might even prove disastrous if in an age in which the influence of the higher religions is declining the primitive faiths which they overcame should again revive.

The notion of natural law rests upon the concept of the Other as continuant that is to say as non-agent in process. We must therefore consider this notion of the ‘continuant’ more closely. To continue is to remain unchanged throughout a period of time. Continuance then is the character of having a being in time that does not alter; and the continuant is that which persists without change. The simplest form of continuance is the occupation of a position for a time without change. But as this is a negative and unreal or purely abstract notion we may disregard it in favour of movement in a straight line. This is what is defined in Newton's first law of motion. The movement of a particle in empty space is an instance of simple continuance. But all continuance is not in this fashion simple. The movement of a particle with a constant acceleration—as defined for instance by Newton's law of gravitation—is equally an instance of continuance. Here there is change of velocity but the rate of change of velocity remains unchanged. Again the oscillation of a pendulum with a frictionless pivot is equally a continuance because the to and fro motion continues without alteration; and if we take into account the friction of the pivot there is still a continuance since the decrease of the amplitude of the oscillation is constant. This enables us to define continuance in a way that is applicable to all cases however complex. Wherever there is something whatever it may be which is a recurrence of the same we are in the presence of a continuant.

Now it is clear that there is an intimate relation between the idea of continuance and the idea of natural law. If we ask what it is that a law of Nature describes the answer must be a recurrent pattern of change. Consider again the oscillating pendulum and suppose a complete absence of frictional interference with its movement. The pendulum then swings from A to B and back again to A along the arc of a circle whose radius is the distance from its pivot. This movement has a positive and a negative phase and these phases are equal and opposite. The whole movement from A back to A recurs without change ad infinitum in the absence of all interference. If we limit our attention to one complete swing we can determine this by measurement. We need only measure the length of the radius the angle subtended by the arc at the pivot and the time that elapses during the complete swing. We can combine these measurements in a suitable mathematical formula. If we then add the assertion that this formula applies without modification to any complete swing of the pendulum we have determined the particular law which governs the oscillation of that pendulum. We see from this that we can determine the whole movement of the pendulum ad infinitum by determining any part of it which exhibits a completed pattern of change—in this case the rhythm of the oscillation; and we can do this because this rhythmic pattern recurs ad infinitum without change. The result is that from this law which is our mathematical formulation of the pattern we can predict the position of the pendulum at any future time we please.

We can go farther than this however. We need not suppose the impossible condition of a complete absence of friction. We may measure the friction actually present in a particular pendulum. Provided we assume that this friction is constant we can incorporate the coefficient of friction in our formula. If however this too is presupposing ideal conditions since the wear and tear on the pivot must modify the friction we may measure the rate of change of friction and assuming that this is constant we may complicate our formula still further by including this constant also. The farther we proceed in this direction the closer our formula approximates to the conditions actually found in Nature and the more exact do our predictions become. The determination of laws of Nature then depends upon the discovery of natural constants; that is to say upon natural continuance.

The laws of which we have been speaking are particular laws; but what is usually meant by a law of Nature is general. These general laws of Nature are derived from the particular laws by generalization. From the formula for a particular frictionless pendulum we can derive a formula for all frictionless pendulums. For in all cases though some elements vary others remain constant. If this were not so they could not be instances of the oscillation of a pendulum. The formulae of the different instances then will exhibit constant elements and variable elements. We can therefore devise a general formula in which the constant elements provide the determinate structure and the variables are represented by special symbols. This is our general law which can be applied in any particular case by determining the value of the variables for that case. In other words the law of a particular instance can be derived from the general law by determining what is variable in it. The general law holds for all instances of a class. If we ask then what makes them all instances of a class the answer will be that the general law applies to them all. If this seems to beg the question—and in a sense it does—we must refer to what has already been said about classification. Clearly before we can determine a general law we must have a principle of classification which is independent of it. But this principle need only be prima facie: it may require modification as our knowledge progresses. Observed resemblances may provide a rough starting-point: but in view of what has already been said about the secondary character of the ‘observational’ point of view it would be at least more fundamental to say that we begin by classifying together all instances in relation to which we find in practice that we can act successfully in the same fashion. The original constants are to be found in our own modes of action for which of course perceptual resemblances are an original if somewhat untrustworthy guide.

A ‘law of Nature’ then is a pattern of continuance and the discovery of such ‘laws’ is the discovery of such patterns in our experience of the Other. To say of any group of phenomena that it obeys a law is to assert that it contains a pattern of change which recurs without change. To say that Nature in general obeys laws or that all phenomena occur in accordance with laws is to assert that Nature is the Continuant or the non-agent in temporal existence.

There are certain observations to be made concerning the process whereby our first practical discrimination of the world is developed through reflection into a scientific understanding of Nature and so confers upon our practical activity a wider range and an increasing exactitude. We must notice that however far we carry it the process depends upon the isolation of recurrent patterns. This has two results which render our conclusions uncertain and liable to endless revision. The first of these is that an element of idealization is always present. In speaking of the law which is obeyed by a frictionless pendulum we were isolating the phenomena which exhibit the recurrent pattern from all phenomena of friction. The result is that we consider an ideal case which can never be actual. But if we then include the element of friction we are still isolating the phenomena included from other phenomena with which the swinging pendulum is in fact inseparably connected; and the case is still idealized. For practical purposes we can isolate the phenomena in accordance with a principle of relevance so that the elements excluded are negligible for our purposes. But theoretically the isolation of elements within the whole must produce an ideal case which is never fully actual and the ‘laws’ which we thus establish apply in principle only subject to a qualification. Actual instances vary from the ideal case within limits. This is at least part of what is meant when it is said that all scientific laws are statistical. Even such a simple determination as that water is H₂O is the setting up of an ideal norm and water which precisely conforms to this rule can only be produced in the laboratory if even there.

The second result concerns the predictions which we base upon these ‘laws’. They must be made with the qualification expressed or understood ‘provided nothing interferes’. The prediction is made on the basis of an ideal isolation from the actual complexity of conditions to which it refers and in which it must be realized. There is therefore always a possibility that some of the factors left out of our calculation may interfere with the realization of our prediction. In the case of the pendulum we may calculate the time at which it will come to rest but only with the proviso that nothing interferes with its freedom to swing; that is to say provided the conditions obtaining when we took our measurements remain constant. This we can never guarantee; although in some cases we may be able to calculate with fair accuracy the probability of a change in the conditions.

This possibility of interference becomes of special importance if we take account of the presence of agents and their intentions. I can calculate when my pendulum will come to rest; but also I can stop it myself at any moment; or I can arrange a mechanism which will keep it swinging indefinitely. The range and accuracy of astronomical predictions and the high degree of certainty they possess depends largely upon the fact that we know of no agents who have the power even had they the will to interfere. It is important therefore to notice this special case of the possibility of personal interference. All our physical predictions depend on an abstraction from the presence of agents with their capacity to determine the future. We must postulate a world in which there is no action; and such a world is itself an ideal isolate a world in which there are no persons. But this can never be the actual world in which we operate. For the process of determining the patterns of recurrence is itself a personal activity which requires experiment; and an experiment is itself a deliberate personal interference with the processes which are observed. What we call the physical world is therefore in all strictness an imaginary world. Even in conception it is the world which we know of which we are part and in which we act imagined as existing without ourselves or any other agents whatsoever in it; a world in which there is no action. Indeed if we are referring to the world as conceived by the physicist it is a world also in which there are no organisms and therefore no responses to stimulus; a world therefore in which there are no stimuli to which an organism might respond.

Now consider the experimental situation without abstraction. To determine the law which governs the movement of the pendulum I erect a pendulum and I set it swinging. Then I begin to take the measurements I need. But during the experiment I do not interfere with its motion. My practical concern is to keep the conditions constant throughout—to prevent interference. When I have made all the measurements I require I stop the pendulum and sit down to study the measurements I have noted. The whole experiment is an action of mine: I do the experiment. But the pattern of movement I observe and the law that I elicit refer only to what happens within my action. I leave out of account my starting the pendulum when I begin and my stopping it when I have finished. The law of the particular instance refers to what happens between these points; to that aspect of my doing the experiment which I do not do; that is to say the negative aspect of my action. If now we call this a causal process we realize in another way that causality is the negative aspect of agency and falls within action.

The ‘I do’ we see again is the necessary starting-point. The ‘it happens’ falls within it in actuality and in conception is abstracted from it. I can always ask ‘What happens when I do something?’ when I drive a car from Glasgow to Edinburgh for example. The question refers to all the elements in my action which do themselves as it were; which are not determined by a deliberate and specific intention of my own. Consequently a complete account of my journey is possible which nowhere refers to any intention of mine. If we please we need not even refer to my bodily movements; but confine the record to the movements of the mechanism of the car. Or if we please we can include the movements of my hands on the steering wheel and gear lever and of my feet on the pedals. Or again we may include reference to my automatic reflexes and responses to stimuli. All these accounts are made possible by a deliberate choice to refrain from asking certain questions which in fact are quite legitimate and which are indeed necessary to a complete understanding. We keep within the field of happening by excluding questions which involve a reference to agency. The moment we ask ‘Why were you going to Edinburgh anyway?’ the tracing of causal processes or continuant patterns must stop because the answer must refer to an intention. ‘Because I live in Edinburgh’ might be a sufficient answer.

We have taken our examples of continuance from the physical field for simplicity's sake. But this does not imply that the organic and personal fields do not equally exhibit continuance. In the organic field indeed it is most immediately impressive. The repetition of the life cycle in successive generations ‘each according to his kind’ has always attracted human attention and interest. Here we clearly find a pattern of change which prima facie repeats itself without change. The theory of an evolution of species requires no modification in principle. If it is spontaneous then the repetition with variation is itself the pattern which repeats and the principle of the successive variations is itself determinable. But it seems more likely that the larger variations and perhaps all variations from type have their ground in some interference or in some change in environmental conditions. The belief that organic development is also determined in accordance with natural law; or—which is in the end the same thing—that for a particular organism the pattern of response to stimulus is determinate is not merely based upon observation. It is a necessity for thought. For the only spontaneous initiation of change which we can conceive is the act of an agent; and whatever is non-agent that is to say non-personal must be conceived as a continuant. Without a ground of change the movement which has been begun must continue without change.

In the personal field this organic continuance appears as habitual activity. Our habits are those elements in our practical activity which are recurrent responses to recurrent stimuli. They differ from instinctive reactions only in the fact that they have to be learned in the first instance and consequently can in principle be unlearned. Normally our habits are continuously qualified by the intentional action within which they fall and which they make possible. All actions depend upon a system of habitual responses to stimuli; and the formation of habits is the necessary basis of every action. If we cross a busy street we concentrate our attention upon our objective and upon traffic to be avoided and determine the direction the changes of direction and the timing of our movements. The rest—and it is the greater part—of our activity is automatically adapted to these conscious determinations. Here habit is clearly the negative aspect of our action without which the action could not take place. It is integrated with and subservient to the positive aspect of deliberate purpose in terms of which the action must be defined. This can be clearly seen by contrast with abnormal cases in which a habit becomes compulsive and escapes from deliberate control. Only then do we find an activity which is purely habitual and for which the agent is not immediately responsible.

Such an autonomous habit is a behaviour pattern which recurs without change. It follows that if we can determine the pattern we can formulate a law which will enable us to predict the future behaviour of the agent in respect of every recurrence of the particular stimulus to which the habit is a response. Now suppose that this particular autonomous habit is common to a group of persons or to all persons. Then the law of the habit could be generalized and the behaviour of all agents in the group could in this respect be predicted. Suppose then that we proceed as psychologists in precisely the same way as the physicist does by abstracting from action and considering only that aspect of personal behaviour which is constituted by habit. We can then study the activities of persons as if they were purely continuant. We can make experiments with normal persons who will agree to behave in accordance with our instructions and not for their own ends and on their own initiative. In this way we can isolate under laboratory conditions those aspects of human behaviour which would normally be habitual responses within deliberate action. Alternatively we may study abnormal individuals suffering from neurotic or psychotic diseases and so observe actual cases of behaviour which is isolated from normal control by the agent. On the basis of such systematic observation we may seek to determine psychological laws of human behaviour in a thoroughly scientific fashion and verify them in the usual way. The knowledge that we obtain can be used just as in the case of physics or biology for the deliberate control of human behaviour.

We must notice particularly that in these respects there is no difference in principle between psychology and physics and that the validity of the laws determined in both cases is in principle the same. Indeed it is physics which is modelled on psychology in the last analysis and not psychology on physics. For it is our experience of habit in ourselves that provides the notion of a recurrent pattern of change from which the conception of a continuant world obeying laws of Nature is derived and apart from which it would be inconceivable. The physicist like the psychologist abstracts from action—his own action in observing and in making experiments—and so constitutes an ideal world which is purely continuant. That in the one case the continuance is ‘external’ to the agent and in the other ‘internal’ makes no essential difference. In both cases the observed continuance falls within action and is conditioned by action. In both cases verification is through practical control based upon knowledge. Now our control of the continuant in action is in fact easier if it is external to ourselves than if it is internal. It is notoriously difficult to alter our own habits by a deliberate effort. There is no such difficulty in controlling the movements of a material object provided that our knowledge and our available resources are adequate. There is of course an empirical difference between the two cases. The patterns of behaviour are much more complex for the psychologist; the difficulty of experiment is greater; the number of instances available is far less so that the reliability of generalization even through the use of statistical methods is greatly diminished. Above all the probability of interference is very much higher. But these are matters of degree not of kind.

We shall conclude by noting three important corollaries of this study of the Continuant. Firstly the substitution of the idea of law for the idea of cause in science does not solve the causal dilemma. It excludes it from consideration by avoiding the question which requires a causal answer. If I observe a process of change I can seek to discover a recurrent pattern in it and so to determine a law of continuance. In doing this however I refrain from asking another question ‘What set the process going in the first instance?’ This is of course the question ‘What is the cause of the process?’ and it is not a senseless question unless we are prepared to deny that the process ever had a beginning. In many cases we can give a definite answer. In the cases in which the process is experimental the answer is that it didn't need a cause since somebody performed the experiment. The generality of natural laws consists in the fact that they apply to all particular instances of a kind; and the number of all particular instances is finite. The replacement of the notion of ‘cause’ by that of ‘law’ is not properly a substitution. It defines a different mode of abstraction or isolation within which the question of a cause does not arise. The incoherence of the conception of ‘cause’ as an agent which is not an agent remains unaffected.

The second corollary is this. Since the ‘worlds’ which are isolated by physics or biology or psychology are imaginary or ideal worlds we have no ground for asserting that the ‘laws’ that science formulates apply without qualification to the actual world in which we live. But since these ideal worlds are derived by systematic and well-grounded abstraction they do fall within the actual world as aspects of it. Since the general abstraction is from action so that these ideal worlds are systems of continuance we are justified in saying that the laws of Nature hold of the actual world in so far as it is a continuant.

The final corollary is that the Continuant has no future. Time we have seen is the form of action. Action distinguishes past from future as the determinate and the undetermined respectively. The determinate is the past and the continuant is already completely determined. Its temporal determination is that of the spatialized time of which we have spoken which is the relative time order within the past and which we can project into the real future in present imagination. The future which we predict for it is really our future as agents. Having known it in the past we shall remember it when we see it again; and what we shall see is what we have already seen. If this is never completely so it is because the continuant is itself an ideal object. In actual experience it is the negative aspect of action and thus it gains a relation to real time which in its own right it does not possess.

• 1. This aspect of the matter has been admirably dealt with in an important article by the late Professor R. G. Collingwood in the Proceedings of the Aristotelian Society for 1937–8 (N. S., Vol. XXXVIII), under the title ‘On the So-called Idea of Causation’.