Taking square aim at Hume’s “Of Liberty and Necessity“, Thomas Reid roundly rejects the compatibility of necessity or determinism and moral responsibility. Instead, he sketches a seminal conception of agent causation.
The Notions of Moral Liberty and Necessity Stated.
By the liberty of a moral agent, I understand, a power over the determinations of his own will.
If, in any action, he had power to will what he did, or not to will it, in that action he is free. But if, in every voluntary action, the determination of his will be the necessary consequence of something involuntary in the state of his mind, or of something in his external circumstances, he is not free; he has not what I call the liberty of a moral agent, but is subject to necessity.
This liberty supposes the agent to have understanding and will; for the determinations of the will are the sole object about which this power is employed; and there can be no will without, at least, such a degree of understanding as gives the conception of that which we will.
The liberty of a moral agent implies, not only a conception of what he wills, but some degree of practical judgment or reason.
For, if he has not the judgment to discern one determination to be preferable to another, either in itself, or for some purpose which he intends, what can be the use of a power to determine? His determinations must be made perfectly in the dark, without reason, motive, or end. They can neither be right nor wrong, wise nor foolish. Whatever the consequences may be, they cannot be imputed to the agent, who had not the capacity of foreseeing them, or of perceiving any reason for acting otherwise than he did.
We may perhaps be able to conceive a being endowed with power over the determinations of his will, without any light in his mind to direct that power to some end. But such power would be given in vain. No exercise of it could be either blamed or approved. As nature gives no power in vain, I see no ground to ascribe a power over the determinations of the will to any being who has no judgment to apply it to the direction of his conduct, no discernment of what we ought or ought not to do.
For that reason, in this Essay, I speak only of the liberty of moral agents, who are capable of acting well or ill, wisely or foolishly, and this, for distinction’s sake I shall call moral liberty.
What kind, or what degree of liberty belongs to brute-animals, or to our own species, before any use of reason, I do not know. We acknowledge that they have not the power of self-government. Such of their actions as may be called voluntary, seem to be invariably determined by the passion or appetite, or affection or habit, which is strongest at the time.
This seems to be the law of their constitution, to which they yield, as the inanimate creation does, without any conception of the law, or any intention of obedience.
But of civil or moral government, which are addressed to the rational powers, and require a conception of the law and an intentional obedience, they are, in the judgment of all mankind, incapable. Nor do I see what end could be served by giving them a power over the determinations of their own will, unless to make them intractable by discipline, which we see they are not.
The effect of moral liberty is, That it is in the power of the agent to do well or ill. This power, like every other gift of God, may be abused. The right use of this gift of God is to do well and wisely, as far as his best judgment can direct him, and thereby merit esteem and approbation. The abuse of it is to act contrary to what he knows or suspects to be his duty and his wisdom, and thereby justly merit disapprobation and blame.
By necessity, I understand the want of that moral liberty which I have above defined.
If there can be a better and a worse in actions on the system of necessity, let us suppose a man necessarily determined in all cases to will and to do what is best to be done, he would surely be innocent and inculpable. But, as far as I am able to judge, he would not be intitled to the esteem and moral approbation of those who knew and believed this necessity. What was, by an ancient author, said of Cato, might indeed be said of him; He was good because he could not be otherwise. But this saying, if understood literally and strictly, is not the praise of Cato, but of his constitution, which was no more the work of Cato, than his existence.
On the other hand, if a man be necessarily determined to do ill, this case seems to me to move pity, but not disapprobation. He was ill, because he could not be otherwise. Who can blame him? Necessity has no law.
If he knows that he acted under this necessity, has he not just ground to exculpate himself? The blame, if there be any, is not in him, but in his constitution. If he be charged by his Maker with doing wrong, may he not expostulate with him, and say, Why hast thou made me thus? I may be sacrificed at thy pleasure, for the common good, like a man that has the plague, but not for ill desert; for thou knowest that what I am charged with is thy work, and not mine.
Such are my notions of moral liberty and necessity, and of the consequences inseparably connected with both the one and the other.
This moral liberty a man may have, though it do not extend to all his actions, or even to all his voluntary actions. He does many things by instinct, many things by the force of habit without any thought at all, and consequently without will. In the first part of life, he has not the power of self-government, any more than the brutes. That power over the determinations of his own will, which belongs to him in ripe years, is limited, as all his powers are; and it is perhaps beyond the reach of his understanding to define its limits with precision. We can only say, in general, that it extends to every action for which he is accountable.
This power is given by his Maker, and at his pleasure whose gift it is. It may be enlarged or diminished, continued or withdrawn. No power in the creature can be independent of the Creator. His hook is in its nose; he can give it line as far as he sees fit, and, when he pleases, can restrain it, or turn it whithersoever he will. Let this be always understood, when we ascribe liberty to man or to any created being.
Supposing it therefore to be true, That man is a free agent it may be true, at the same time that his liberty may be impaired or lost by disorder of body or mind, as in melancholy or in madness; it may be impaired or lost by vicious habits; it may in particular cases be restrained by divine interposition.
We call man a free agent in the same way as we call him a reasonable agent. In many things he is not guided by reason, but by principles similar to those of the brutes. His reason is weak at best. It is liable to be impaired or lost, by his own fault, or by other means. In like manner, he may be a free agent, though his freedom of action may have many similar limitations.
The liberty I have described has been represented by some philosophers as inconceivable, and as involving an absurdity.
“Liberty,” they say, “consists only in a power to act as we will; and it is impossible to conceive in any being a greater liberty than this. Hence it follows, that liberty does not extend to the determinations of the will, but only to the actions consequent to its determination, and depending upon the will. To say that we have power to will such an action, is to say, that we may will it, if we will. This supposes the will to be determined by a prior will; and, for the same reason, that will must be determined by a will prior to it, and so on in an infinite series of wills, which is absurd. To act freely, therefore, can mean nothing more than to act voluntarily; and this is all the liberty that can be conceived in man, or in any being.”
This reasoning, first, I think, advanced by Hobbes, has been very generally adopted by the defenders of necessity. It is grounded upon a definition of liberty totally different from that which I have given, and therefore does not apply to moral liberty, as above defined.
But it is said that this is the only liberty that is possible, that is conceivable, that does not involve an absurdity.
It is strange, indeed! if the word liberty has no meaning but this one. I shall mention three, all very common. The objection applies to one of them, but to neither of the other two.
Liberty is sometimes opposed to external force or confinement of the body. Sometimes it is opposed to obligation by law, or by lawful authority. Sometimes it is opposed to necessity.
- It is opposed to confinement of the body by superior force. So we say a prisoner is set at liberty when his fetters are knocked off, and he is discharged from confinement. This is the liberty defined in the objection: and I grant that this liberty extends not to the will, neither does the confinement, because the will cannot be confined by external force.
- Liberty is opposed to obligation by law, or lawful authority. This liberty is a right to act one way or another, in things which the law has neither commanded nor forbidden; and this liberty is meant when we speak of a man’s natural liberty, his civil liberty, his Christian liberty. It is evident that this liberty, as well as the obligation opposed to it, extends to the will: for it is the will to obey that makes obedience; the will to transgress that makes a transgression of the law. Without will there can be neither obedience nor transgression. Law supposes a power to obey or to transgress; it does not take away this power, but proposes the motives of duty and of interest, leaving the power to yield to them, or to take the consequence of transgression.
- Liberty is opposed to necessity, and in this sense it extends to the determinations of the will only, and not to what is consequent to the will.
In every voluntary action, the determination of the will is the first part of the action, upon which alone the moral estimation of it depends. It has been made a question among philosophers, Whether, in every instance, this determination be the necessary consequence of the constitution of the person, and the circumstances in which he is placed; or whether he had not power, in many cases, to determine this way or that?
This has, by some, been called the philosophical notion of liberty and necessity; but it is by no means peculiar to philosophers. The lowest of the vulgar have, in all ages, been prone to have recourse to this necessity, to exculpate themselves or their friends in what they do wrong, though, in the general tenor of their conduct, they act upon the contrary principle.
Whether this notion of moral liberty be conceivable or not, every man must judge for himself. To me there appears no difficulty in conceiving it. I consider the determination of the will as an effect. This effect must have a cause which had power to produce it; and the cause must be either the person himself, whose will it is, or some other being. The first is as easily conceived as the last. If the person was the cause of that determination of his own will, he was free in that action, and it is justly imputed to him, whether it be good or bad. But if another being was the cause of this determination, either by producing it immediately, or by means and instruments under his direction, then the determination is the act and deed of that being, and is solely imputable to him.
But it is said, “That nothing is in our power but what depends upon the will, and therefore the will itself cannot be in our power.”
I answer, That this is a fallacy arising from taking a common saying in a sense which it never was intended to convey, and in a sense contrary to what it necessarily implies.
In common life, when men speak of what is, or is not, in a man’s power, they attend only to the external and visible effects, which only can be perceived, and which only can affect them. Of these, it is true, that nothing is in a man’s power but what depends upon his will, and this is all that is meant by this common saying.
But this is so far from excluding his will from being in his power, that it necessarily implies it. For to say that what depends upon the will is in a man’s power, but the will is not in his power, is to say that the end is in his power, but the means necessary to that end are not in his power, which is a contradiction.
In many propositions which we express universally, there is an exception necessarily implied, and therefore always understood. Thus when we say that all things depend upon God, God himself is necessarily excepted. In like manner, when we say, that all that is in our power depends upon the will, the will itself is necessarily excepted: for if the will be not, nothing else can be in our power. Every effect must be in the power of its cause. The determination of the will is an effect, and, therefore, must be in the power of its cause, whether that cause be the agent himself, or some other being.
From what has been said in this chapter, I hope the notion of moral liberty will be distinctly understood, and that it appears that this notion is neither inconceivable, nor involves any absurdity or contradiction.
Of the Words Cause and Effect, Action, and Active Power
The writings upon liberty and necessity have been much darkened by the ambiguity of the words used in reasoning upon that subject. The words cause and effect, action and active power, liberty and necessity, are related to each other: the meaning of one determines the meaning of the rest. When we attempt to define them, we can only do it by synonymous words which need definition as much. There is a strict sense in which those words must be used, if we speak and reason clearly about moral liberty; but to keep to this strict sense is difficult, because in all languages they have, by custom, got a great latitude of signification.
As we cannot reason about moral liberty without using those ambiguous words, it is proper to point out, as distinctly as possible, their proper and original meaning, in which they ought to be understood in treating of this subject, and to show from what causes they have become so ambiguous in all languages, as to darken and embarrass our reasonings upon it.
Every thing that begins to exist, must have a cause of its existence, which had power to give it existence. And every thing that undergoes any change, must have some cause of that change.
That neither existence, nor any mode of existence, can begin without an efficient cause, is a principle that appears very early in the mind of man; and it is so universal, and so firmly rooted in human nature, that the most determined scepticism cannot eradicate it.
It is upon this principle that we ground the rational belief of a deity. But that is not the only use to which we apply it. Every man’s conduct is governed by it every day, and almost every hour of his life. And if it were possible for any man to root out this principle from his mind, he must give up every thing that is called common prudence, and be fit only to be confined as insane.
From this principle it follows, That every thing which undergoes any change, must either be the efficient cause of that change in itself, or it must be changed by some other being.
In the first case it is said to have active power, and to act in producing that change. In the second case it is merely passive, or is acted upon, and the active power is in that being only which produces the change.
The name of a cause and of an agent is properly given to that being only, which, by its active power, produces some change in itself, or in some other being. The change, whether it be of thought, of will, or of motion, is the effect. Active power, therefore, is a quality in the cause, which enables it to produce the effect. And the exertion of that active power in producing the effect, is called action, agency, efficiency.
In order to the production of any effect, there must be in the cause, not only power, but the exertion of that power: for power that is not exerted produces no effect.
All that is necessary to the production of any effect, is power in an efficient cause to produce the effect, and the exertion of that power: for it is a contradiction to say, that the cause has power to produce the effect, and exerts that power, and yet the effect is not produced. The effect cannot be in his power unless all the means necessary to its production be in his power.
It is no less a contradiction to say, that a cause has power to produce a certain effect, but that he cannot exert that power: for power which cannot be exerted is no power, and is a contradiction in terms.
To prevent mistake, it is proper to observe, That a being may have a power at one time which it has not at another. It may commonly have a power, which at a particular time, it has not. Thus, a man may commonly have power to walk or to run; but he has not this power when asleep, or when he is confined by superior force. In common language, he may be said to have a power which he cannot then exert. But this popular expression means only that he commonly has this power, and will have it when the cause is removed which at present deprives him of it: for when we speak strictly and philosophically, it is a contradiction to say that he has this power, at that moment when he is deprived of it.
These, I think, are necessary consequences from the principle first mentioned, That every change which happens in nature must have an efficient cause which had power to produce it.
Another principle, which appears very early in the mind of man, is, That we are efficient causes in our deliberate and voluntary actions.
We are conscious of making an exertion, sometimes with difficulty, in order to produce certain effects. An exertion made deliberately and voluntarily, in order to produce an effect, implies a conviction that the effect is in our power. No man can deliberately attempt what he does not believe to be in his power. The language of all mankind, and their ordinary conduct in life, demonstrate, that they have a conviction of some active power in themselves to produce certain motions in their own and in other bodies, and to regulate and direct their own thoughts. This conviction we have so early in life, that we have no remembrance when, or in what way, we acquired it.
That such a conviction is at first the necessary result of our constitution, and that it can never be entirely obliterated, is, I think, acknowledged by one of the most zealous defenders of necessity. Free discussion, &c. p. 298. “Such are the influences to which all mankind, without distinction, are exposed, that they necessarily refer actions (I mean refer them ultimately) first of all to themselves and others; and it is a long time before they begin to consider themselves and others as instruments in the hand of a superior agent. Consequently, the associations which refer actions to themselves, get so confirmed, that they are never entirely obliterated; and therefore the common language, and the common feelings of mankind, will be adapted to the first, the limited and imperfect, or rather erroneous view of things.”
It is very probable, that the very conception or idea of active power, and of efficient causes, is derived from our voluntary exertions in producing effects; and that, if we were not conscious of such exertions, we should have no conception at all of a cause, or of active power, and consequently no conviction of the necessity of a cause of every change which we observe in nature.
It is certain that we can conceive no kind of active power but what is similar or analogous to that which we attribute to ourselves; that is, a power which is exerted by will and with understanding. Our notion, even of almighty power, is derived from the notion of human power, by removing from the former those imperfections and limitations to which the latter is subjected.
It may be difficult to explain the origin of our conceptions and belief concerning efficient causes and active power. The common theory, that all our ideas are ideas of sensation or reflection, and that all our belief is a perception of the agreement or the disagreement of those ideas, appears to be repugnant, both to the idea of an efficient cause, and to the belief of its necessity.
An attachment to that theory has led some philosophers to deny that we have any conception of an efficient cause, or of active power, because efficiency and active power are not ideas, either of sensation or reflection. They maintain, therefore, that a cause is only something prior to the effect, and constantly conjoined with it. This is Mr. Hume’s notion of a cause, and seems to be adopted by Dr. Priestley, who says, “That a cause cannot be defined to be any thing, but such previous circumstances as are constantly followed by a certain effect, the constancy of the result making us conclude, that there must be a sufficient reason, in the nature of the things, why it should be produced in those circumstances.”
But theory ought to stoop to fact, and not fact to theory. Every man who understands the language knows, that neither priority, nor constant conjunction, nor both taken together, imply efficiency. Every man, free from prejudice, must assent to what Cicero has said: ltaque non sic causa intelligi debet, ut quod cuique antecedat, id et causa sit, sed quod cuique efficienter antecedit. ,
The very dispute, whether we have the conception of an efficient cause, shows that we have. For though men may dispute about things which have no existence, they cannot dispute about things of which they have no conception.
What has been said in this chapter is intended to show, That the conception of causes, of action and of active power, in the strict and proper sense of these words, is found in the minds of all men very early, even in the dawn of their rational life. It is therefore probable, that, in all languages, the words by which these conceptions were expressed were at first distinct and unambiguous, yet it is certain, that, among the most enlightened nations, these words are applied to so many things of different natures, and used in so vague a manner, that it is very difficult to reason about them distinctly.
This phenomenon, at first view, seems very unaccountable. But a little reflection may satisfy us, that it is a natural consequence of the slow and gradual progress of human knowledge.
And since the ambiguity of these words has so great influence upon our reasoning about moral liberty, and furnishes the strongest objections against it, it is not foreign to. our subject to show whence it arises. When we know the causes that have produced this ambiguity, we shall be less in danger of being misled by it, and the proper and strict meaning of the words will more evidently appear.
CAUSES Of THE AMBIGUITY OF THOSE WORDS.
When we turn our attention to external objects, and begin to exercise our rational faculties about them, we find, that there are some motions and changes in them, which we have power to produce, and that they have many which must have some other cause. Either the objects must have life and active power, as we have, or they must be moved or changed by something that has life and active power, as external objects are moved by us.
Our first thoughts seem to be, That the objects in which we perceive such motion have understanding and active power as we have.
“Savages,” says the Abbe Raynal, “wherever they see motion which they cannot account for, there they suppose a soul.”
All men may be considered as savages in this respect, until they are capable of instruction, and of using their faculties in a more perfect manner than savages do.
The rational conversations of birds and beasts in jEsop’s Fables do not shock the belief of children. To them they have that probability which we require in an epic poem. Poets give us a great deal of pleasure, by clothing every object with intellectual and moral attributes in metaphor and in other figures. May not the pleasure which we take in this poetical language arise, in part, from its correspondence with our earliest sentiments?
However this may be, the Abbé Raynal’s observation is sufficiently confirmed, both from fact, and from the structure of all languages.
Rude nations do really believe sun, moon, and stars, earth, sea, and air, fountains and lakes, to have understanding and active power. To pay homage to them, and implore their favour, is a kind of idolatry natural to savages.
All languages carry in their structure the marks of their being formed when this belief prevailed. The distinction of verbs and participles into active and passive, which is found in all languages, must have been originally intended to distinguish what is really active from what is merely passive; and, in all languages, we find active verbs applied to those objects, in which, according to the Abbé Raynal’s observation, savages suppose a soul.
Thus we say the sun rises and sets, and comes to the meridian, the moon changes, the sea ebbs and flows, the winds blow. Languages were formed by men who believed those objects to have life and active power in themselves. It was therefore proper and natural to express their motions and changes by active verbs.
There is no surer way of tracing the sentiments of nations before they have records than by the structure of their language, which, notwithstanding the changes produced in it by time, will always retain some signatures of the thoughts of those by whom it was invented. When we find the same sentiments indicated in the structure of all languages, those sentiments must have been common to the human species when languages were invented.
When a few of superior intellectual abilities find leisure for speculation, they begin to philosophise, and soon discover, that many of those objects which at first they believed to be intelligent and active, are really lifeless and passive. This is a very important discovery. It elevates the mind, emancipates from many vulgar superstitions, and invites to farther discoveries of the same kind.
As philosophy advances, life and activity in natural objects retires, and leaves them dead and inactive. Instead of moving voluntarily, we find them to be moved necessarily; instead of acting, we find them to be acted upon; and nature appears as one great machine, where one wheel is turned by another, that by a third; and how far this necessary succession may reach, the philosopher does not know.
The weakness of human reason makes men prone, when they leave one extreme, to rush into the opposite; and thus philosophy, even in its infancy, may lead men from idolatry and polytheism into atheism, and from ascribing active power to inanimate beings to conclude all things to be carried on by necessity.
Whatever origin we ascribe to the doctrines of atheism and of fatal necessity, it is certain, that both may be traced almost as far back as philosophy; and both appear to be the opposites of the earliest sentiments of men.
It must have been by the observation and reasoning of the speculative few, that those objects were discovered to be inanimate and inactive, to which the many ascribed life and activity. But while the few are convinced of this, they must speak the language of the many in order to be understood. So we see, that when the Ptolemaic system of astronomy. which agrees with vulgar prejudice and with vulgar language, has been universally rejected by philosophers, they continue to use the phraseology that is grounded upon it, not only in speaking to the vulgar, but in speaking to one another. They say, The sun rises and sets, and moves annually through all the signs of the zodiac, while they believe that he never leaves his place.
In like manner, those active verbs and participles, which were applied to the inanimate objects of nature, when they were believed to be really active, continue to be applied to them after they are discovered to be passive.
The forms of language, once established by custom, are not so easily changed as the notions on which they were originally founded. While the sounds remain, their signification is gradually enlarged or altered- This is sometimes found, even in those sciences in which the signification of words is the most accurate and precise. Thus, in arithmetic, the word number, among the ancients, always signified so many units, and it would have been absurd to apply it either to unity, or to any part of an unit; but now we call unity, or any part of unity, a number. With them, multiplication always increased a number, and division diminished it; but we speak of multiplying by a fraction, which diminishes, and of dividing by a fraction, which increases the number. We speak of dividing or multiplying by unity, which neither diminishes nor increases a number. These forms of expression, in the ancient language, would have been absurd.
By such changes in the meaning of words, the language of every civilized nation resembles old furniture new modelled, in which many things are put to uses for which they were not originally intended, and for which they are not perfectly fitted.
This is one great cause of the imperfection of language, and it appears very remarkably in those verbs and participles which are active in their form, but are frequently used so as to have nothing active in their signification.
Hence we are authorised by custom to ascribe action and active power to things which we believe to be passive. The proper and original signification of every word, which at first signified action and causation, is buried and lost under that vague meaning which custom has affixed to it.
That there is a real distinction, and perfect opposition, between acting and being acted upon, every man may be satisfied who is capable of reflection. And that this distinction is perceived by all men as soon as they begin to reason, appears by the distinction between active and passive verbs, which is original in all languages, though, from the causes that have been mentioned, they come to be confounded in the progress of human improvement.
Another way in which philosophy has contributed very much to the ambiguity of the words under our consideration, deserves to be mentioned.
The first step into natural philosophy, and what hath commonly been considered as its ultimate end, is the investigation of the causes of the phenomena of nature; that is, the causes of those appearances in nature which are not the effects of human power. Felix qui potuit rerum cognosces causus, is the sentiment of every mind that has a turn to speculation.
The knowledge of the causes of things promises no less the enlargement of human power than the gratification of human curiosity; and therefore, among the enlightened part of mankind this knowledge has been pursued in all ages with an avidity proportioned to its importance.
In nothing does the difference between the intellectual powers of man and those of brutes appear more conspicuous than in this. For in them we perceive no desire to investigate the causes of things, nor indeed any sign that they have the proper notion of a cause.
There is reason, however, to apprehend, that, in this investigation, men have wandered much in the dark, and that their success has by no means been equal to their desire and expectation.
We easily discover an established order and connexion in the phenomena of nature. We learn, in many cases, from what has happened, to know what will happen. The discoveries of this kind, made by common observation, are many, and are the foundation of common prudence in the conduct of life. Philosophers, by more accurate observation and experiment, have made many more; by which arts are improved, and human power, as well as human knowledge, is enlarged.
But, as to the real causes of the phenomena of nature, how little do we know! All our knowledge of things external must be grounded ulion the information of our senses : but causation and active power are not objects of sense; nor is that always the cause of a phenomenon which is prior to it, and constantly conjoined with it; otherwise night would be the cause of day, and day the cause of the following night.
It is to this day problematical, whether all the phenomena of the material system be produced by the immediate operation of the First Cause, according to the laws which his wisdom determined, or whether subordinate causes are employed by him in the operations of nature; and if they be, what their nature, their number, and their different offices are? And whether, in all cases, they act by commission, or, in some, according to their discretion.
When we are so much in the dark with regard to the real causes of the phenomena of nature, and have a strong desire to know them, it is not strange, that ingenious men should form numberless conjectures and theories, by which the soul, hungering for knowledge, is fed with chaff instead of wheat.
In a very ancient system, love and strife were made the causes of things: in the Pythagorean and Platonic system, matter, ideas, and an intelligent mind: by Aristotle, matter, form and privation. Des Cartes thought, that matter, and a certain quantity of motion given at first by the Almighty, are sufficient to account for all the phenomena of the natural world: Leibnitz, that the universe is made up of monades, active and percipient, which, by their active power received at first, produce all the changes they undergo.
While men thus wandered in the dark in search of causes, unwilling to confess their disappointment, they vainly conceived every thing they stumbled upon to be a cause, and the proper notion of a cause is lost, by giving the name to numberless things, which neither are nor can be causes.
This confusion of various things under the name of causes is the more easily tolerated, because however hurtful it may be to sound philosophy, it has little influence upon the concerns of life. A constant antecedent, or concomitant, of the phenomenon whose cause is sought, may answer the purpose of the inquirer, as well as if the real cause were known. Thus a sailor desires to know the cause of the tides, that he may know when to expect high water: he is told that it is high water when the moon is so many hours past the meridian: and now he thinks he knows the cause of the tides. What he takes for the cause, answers his purpose, and his mistake does him no harm.
Those philosophers seem to have had the justcst views of nature, aswell as of the weakness of human understanding, who, giving up the pretence of discovering the causes of the operations of nature, have applied themselves to discover, by observation and experiment, the rules, or laws of nature according to which the phenomena of nature are produced.
In compliance with custom, or, perhaps, to gratify the avidity of knowing the causes of things, we call the laws of nature causes and active powers. So we speak of the powers of gravitation, of magnetism, of electricity.
We call them causes of many of the phenomena of nature; and such they are esteemed by the ignorant, and by the half-learned.
But those of juster discernment see, that laws of nature are not agents. They are not endowed with active power, and therefore cannot be causes in the proper sense. They arc only the rules according to which the unknown cause acts.
Thus, it appears, that our natural desire to know the causes of the phenomena of nature, our inability to discover them, and the vain theories of philosophers employed in this search, have made the word cause, and the related words, so ambiguous, and to signify so many things of different natures, that they have in a manner lost their proper and original meaning, and yet we have no other words to express it.
Every thing joined with the effect, and prior to it, is called its cause. An instrument, an occasion, a reason, a motive, an end, are called causes. And the related words effect, agent, power, are extended in the same vague manner.
Were it not that the terms cause and agent have lost their proper meaning, in the crowd of meanings that have been given them, we should immediately perceive a contradiction in the terms necessary cause and necessary agent. And although the loose meaning of those words is authorised by custom, the arbiter of language, and therefore cannot be censured, perhaps cannot always be avoided, yet we ought to be upon our guard, that we be not misled by it to conceive things to be the same which are essentially different.
To say that man is a free agent, is no more than to say, that in some instances he is truly an agent, and a cause, and is not merely acted upon as a passive instrument. On the contrary, to say that he acts from necessity, is to say that he does not act at all, that he is no agent, and that, for any thing we know, there is only one agent in the universe, who does every thing that is done, whether it be good or ill.
If this necessity be attributed even to the Deity, the consequence must be, that there neither is, nor can be, a cause at all; that nothing acts, but every thing is acted upon; nothing moves, but every thing is moved; all is passion without action; all instrument without an agent; and that every thing that is, or was, or shall be, has that necessary existence in its season, which we commonly consider as the prerogative of the First Cause.
This I take to be the genuine, and the most tenable, system of necessity. It was the system of Spinosa, though he was not the first that advanced it; for it is very ancient. And if this system be true, our reasoning to prove the existence of a first cause of every thing that begins to exist, must be given up as fallacious.
If it be evident to the human understanding, as I take it to be, That what begins to exist must have an efficient cause, which had power to give or not to give it existence; and if it be true, that effects well and wisely fitted for the best purposes, demonstrate intelligence, wisdom, and goodness, in the efficient cause, as well as power, the proof of a Deity from these principles is very easy and obvious to all men that can reason.
If, on the other hand, our belief that every thing that begins to exist has a cause, be got only by experience; and if, as Mr. Hume maintains, the only notion of a cause be something prior to the effect, which experience has shown to be constantly conjoined with such an effect, I see not how, from these principles, it is possible to prove the existence of an intelligent cause of the universe.
Mr. Hume seems to me to reason justly from his definition of a cause, when, in the person of an Epicurean, he maintains, that with regard to a cause of the universe, we can conclude nothing; because it is a singular effect. We have no experience that such effects are always conjoined with such a cause. Nay, the cause which we assign to this effect, is a cause which no man hath seen, nor can see, and therefore experience cannot inform us that it has ever been conjoined with any effect. He seems to me to reason justly from his definition of a cause, when he maintains, that any thing may be the cause of any thing; since priority and constant conjunction is all that can be conceived in the notion of a cause.
Another zealous defender of the doctrine of necessity says, that “A cause cannot be defined to be any thing but such previous circumstances as are constantly followed by a certain effect; the constancy of the result making us conclude, that there must be a sufficient reason, in the nature of things, why it should be produced in those circumstances.”
This seems to me to be Mr. Hume’s definition of a cause in other words, and neither more nor less; but I am far from thinking that the author of it will admit the consequences which Mr. Hume draws from it, however necessary they may appear to others.