Reid, Thomas (1710–1796)

4. Motivation and action

Faced with a deterministic universe the particles of which are initially set in motion by a Deity who prescribes Newton’s laws of motion for them, it is hard to see how anything that happens to particles can be an action of mine. What I call my actions would seem to become mere movements of masses of particles, given that I am such a mass. But even if we do not accept this simple picture, problems remain. To say that people act is, Reid thinks, to say that we are efficient causes. How might that status be established for us? Reid responds by claiming (1788: I.vi) that it is a first principle that I am the cause that has power to produce certain motions of my body and directions of my thought.

Reid admits the fact of an established harmony between our willing certain motions of our bodies and the operations of the appropriate nerves and muscles. Now the willing is an act of the mind; but whether it has any physical effect upon the nerves and muscles, or whether it is only an occasion of their being acted upon by some other efficient cause according to established laws of nature, is not known to us. ‘This may leave some doubt whether we be, in the strictest sense, the efficient cause of the voluntary motions of our own body’ (1788: I.vii). He continues: ‘The man who knows that such an event depends upon his will, and who deliberately wills to produce it is, in the strictest moral sense the cause of the event; and the event is justly imputed to him, no matter what physical causes may have concurred in its production.’ However Reid has just shown that it is far from clear that the motion depends upon his will. For he has correctly pointed out that, for all we can know, the volition is at best an occasional cause of the operations of the nerves and muscles. Moreover, he holds that occasional causation, as in the case of night following day, does not of itself amount to physical causation. So unless Reid is willing to allow that dependency can be instanced by occasional causation, there is no clear sense in which the bodily movement depends upon the will.

Reid maintains (1788: IV) that for a bodily movement to be rated as an action of a free agent it is not sufficient that there arise a determination of the will that the movement be produced; it is also required that the agent deliberately willed to produce it. Indeed if they cannot discern one determination to be preferable to another, and thereby exercise their power to choose, their determinations can be neither right nor wrong, wise nor foolish. It is when an agent exercises their active power to determine, or decide upon, their course of action that they act with the liberty of a moral agent. Now the difficulty about whether we are in the strictest sense the cause of so-called voluntary bodily movements emerges once again at the level of voluntary determinations of the will.

The determination of the will the fulfilment of which is my bodily movement must have a cause which had power to produce it. Now the cause is either myself or some other being. But we must ask in what circumstances a determination of will to move my right arm up rates as caused by me. Clearly, first, I must have the power to bring about the determination. Second, the only way in which the exercise of power is conceivable is via a determination of the will. So the only way in which I can conceive of a determination of the will being caused by me is via a prior determination of my will. But what if that prior determination of the will is not brought about by me? Then it would appear that the prior determination – the determination via which my decision to raise my arm up was formed – was either the product of another agent or of myself. In the former case the decision to raise my arm up was not an exercise of moral liberty. Let us remember, however, that it does not follow from the contention that an exercise of active power without will is not clearly conceivable by us that it is impossible.

What is the alternative to the belief that we are efficient causes with moral liberty? We might think that every event, including thoughts and actions, has a physical cause, arguing that if thinking and behaviour are not governed by universal exceptionless laws, they must be random, and consequently that rewards and punishments are without effect. Arguably every deliberate action must have a motive. When there is no conflicting motive this motive must cause us to act. When there are contrary motives the strongest must prevail.

Reid confronts such positions vigorously in (1788: IV.iv). Whether every deliberate action must have a motive depends upon how we understand deliberation. If deliberation means the weighing of motives, then there must be motives – and conflicting ones at that. But if a deliberate action means only an action done through a cool and calm determination, it is not clear that such determinations must be reached by weighing. Consider a case where an end of some importance may be achieved equally well by various means, none of which has any special appeal to the agent. Again the position that when there is a motive on only one side that motive must determine the action ignores such factors as caprice, quite apart from its presumption that motives are the sole causes of actions. But many motives, such as money, or success, are often not even things that exist, but entia rationis (mental constructions), which may best be compared to advice or exhortation, leaving the agent still at liberty to choose. However, we can find entities to serve as occasional causes of determinations such as the desire for money.

When it is said of conflicting motives that the strongest always prevails, Reid rightly points out that this cannot be affirmed or denied with understanding until we know what is meant by the strongest motive. Reid allows that when the contrary motives are of the same kind and differ only in quantity it may be easy to say which is the strongest. Thus a bribe of a thousand pounds is a stronger inducement than one of a hundred pounds. But when the motives are of different kinds, as are money and integrity, we have no rule by which to judge which is the stronger. If we go for prevalence, then the strongest motive would simply be the one that prevailed and the maxim would be trivially true.

These remarks would seem to apply to motives such as hunger and lust, which we have in common with ‘the brutes’. Reid maintains that in their case the strongest motive always prevails, since brutes lack self-command. But this must be so on the trivial interpretation of the maxim. Reid claims that in contrast humankind judges the strength of its appetites by the conscious effort which is needed to resist them. And since it is possible for a person to resist with effort a strong appetite, the strongest appetite does not always prevail (see Desire).

What of rational motives? An interesting example is our good ‘upon the whole’ – that which, taken with all its discoverable connections and consequences, brings more good than ill. Another is our duty. No sooner do we have the former conception than we are ‘led by our constitution’ to seek the good and avoid the ill. So perhaps rational principles of action motivate by themselves. Reid characterises some rational motives as the conviction of what we ought to do in order to achieve some end we have judged fit to be pursued. Such motives may very properly be compared to advocates pleading at the bar. To say that an advocate was the more powerful pleader because judgment was given on their side would be unsatisfactory; once again strength does not guarantee prevalence (see Action).