Collins, like Hume, followed Thomas Hobbes, who defined liberty (or freedom) as being free from external compulsion, what today we call freedom of action. William James called this "soft determinism" and today it is known as compatibilism. This means human choices are determined by necessity (either or both moral and physical necessity). Where Clarke claimed that moral necessity was simply self-determination for good reasons and not predetermination, Collins claimed it was as necessary as physical necessity, even as he thought it essentially different from the mechanical necessity of clocks, for example.

In the explanatory preface to his 1717 essay, A Philosophical Inquiry Concerning Human Liberty, Collins says,

Too much care cannot be taken to prevent being misunderstood and prejudged in handling questions of such nice speculation as those of Liberty and Necessity; and therefore, though I might in justice expect to be read before any judgment be passed on me, I think it proper to premise the following observations.

1. First, though I deny Liberty, in a certain meaning of that word, yet I contend for Liberty as it signifies a power in man to do as he wills, or pleases; which is the notion of Liberty maintained by Aristotle, Cicero, Mr. Locke, and several other philosophers, ancient and modern; and indeed, after a careful examination of the best authors who have treated of Liberty, I may affirm that, however opposite they appear in words to one another, and how much soever some of them seem to maintain another notion of liberty, yet at the bottom, there is an almost universal agreement in the notion defended by me, and all that they say, when examined, will be found to amount to no more.

2. Secondly, when I affirm Necessity, I contend only for what is called Moral Necessity, meaning thereby, that man, who is an intelligent and sensible being, is determined by his reason and his senses; and I deny man to be subject to such necessity as is in clocks, watches, and such other beings, which for want of sensation and intelligence, are subject to an absolute, physical, or mechanical necessity. And here also I have the concurrence of almost all the greatest asserters of Liberty, who either expressly maintain moral necessity, or the thing signified by those words.

3. Thirdly, I have undertaken to show, that the notions I advance, are so far from being inconsistent with, that they are the sole foundations of morality and laws and of rewards and punishments in society and that the notions I explode are subversive of them. This I judged necessary to make out, in treating a subject that has a relation to Morality, because nothing can be true which subverts those things; and all discourse must be defective wherein the reader perceives any disagreement to moral truth; which is as evident as any speculative truth, and much more necessary to be rendered clear to the reader's mind than truth in all other sciences.

4. Fourthly, I have entitled my discourse, a Philosophical Enquiry, etc. because I propose only to prove my point by experience and by reason, omitting all considerations strictly theological. By this method I have reduced the matter to a short compass; and hope I shall give no less satisfaction than if I had considered it also theological; for all but enthusiasts] must think true theology consistent with reason, and with experience.

5. Fifthly, if any should ask of what use such a discourse is, I might offer to their consideration, first, the usefulness of truth in general; and secondly, the usefulness of the truths I maintain towards establishing laws and morality, rewards and punishments in society; hut shall content myself with observing, that it may be of use to all those who desire to know the truth in the questions that I handle, and that think examination the proper means to arrive at that knowledge. As for those who either make no inquiries at all, and concern not themselves about any speculations; or who take up with speculations without any examination; or who read only books to confirm themselves in the speculations they have received — I allow my book to be of no use to them, but yet think they may allow others to enjoy a taste different from their own.

(A Philosophical Inquiry Concerning Human Liberty, pp. xix-xx. Google Scholar)

In his essay, Collins reconciled God's foreknowledge and pre-destination (pre-determinism) with the freedom of human agents. His was not the mysterious position of the Catholic church, that God knows the future, but despite that, humans are free. It was the idea that freedom is consistent with being determined by a logical and necessitated chain of causes going back to the creation of the world. We are free from that logical causal chain as long as we are not in physical chains, externally constrained or compelled by others.

This idea goes back to the Stoic Chrysippus and is what William James later called "soft determinism" and we now call compatibilism or "compatibilist free will," as compared to libertarianism and "libertarian free will."

Like most philosophers who consider the history of philosophy, Collins finds that the problem of free will, opposing the concepts of liberty and necessity, has been the most vexing of all philosophical problems over the centuries,

It is a common observation, even among the learned, that there are certain matters of speculation about which it is impossible, from the nature of the subjects themselves, to speak clearly and distinctly. Upon which account men are very indulgent to, and pardon the unintelligible discourses of theologers and philosophers, which treat of the sublime points in theology and philosophy. And there is no question in the whole compass of speculation of which men have written more obscurely, and of which it is thought more impossible to discourse clearly, and concerning which men more expect and pardon obscure discourse, than upon the subjects of Liberty and Necessity.

(A Philosophical Inquiry Concerning Human Liberty, pp. 21-22. Google Scholar)

Collins begins by stating the question before us.

Man is a necessary agent, if all his actions are so determined by the causes preceding each action, that not one past action could possibly not have come to pass, or have been otherwise than it hath been; nor one future action can possibly not come to pass, or be otherwise than it shall he. He is a free agent, if he is able, at any time under the circumstances and causes he then is, to do different things; or, in other words, if he is not unavoidably determined in every point of time by the circumstances he is in, and the causes he is under, to do that one thing he does, and not possibly to do any other.

(A Philosophical Inquiry Concerning Human Liberty, p. 25. Google Scholar)

The vulgar, who are bred up to believe Liberty or Freedom, think themselves secure of success, constantly appealing to experience for a proof of their freedom, and being persuaded that they feel themselves free on a thousand occasions. And the source of their mistake, seems to be as follows. They either attend not to, or see not the causes of their actions, especially in matters of little moment, and thence conclude they are free, or not moved by causes, to do what they do.

They also frequently do actions whereof they repent; and because in the repenting humor they find no present motive to do those actions, they conclude that they might not have done them at the time they did them, and that they were free from necessity (as they were from outward impediments) in the doing them.

They also find that they can do as they will, and forbear as they will, without any external impediment to hinder them from doing as they will; let them will either doing or forbearing. They likewise see that they often change their minds; that they can, and do choose differently every successive moment; and that they frequently deliberate, and thereby are sometimes at a near balance, and in a state of indifference with respect to judging about some propositions, and willing or choosing with respect to some objects. And experiencing these things they mistake them for the exercise of Freedom, or Liberty from Necessity. For ask them whether they think themselves free, and they will immediately answer, Yes; and say some one or other of these foregoing things, and particularly think they prove themselves free when they affirm they can do as they will.

(A Philosophical Inquiry Concerning Human Liberty, pp. 26-27. Google Scholar)

Collins provides an extensive history of libertarian accounts of free will worth quoting at length.

Celebrated philosophers and theologers, both ancient and modern, who have meditated much on this matter, talk after the same manner, giving definitions of Liberty that are consistent with Fate or Necessity although, at the same time, they would be thought to exempt some of the actions of man from the power of Fate, or to assert Liberty from Necessity. Cicero defines Liberty to be a power to do as we will. And therein several moderns follow him. One defines Liberty to be a power to act, or not to act, as we will. Another defines it in more words thus: "A power to do what we will, and because we will; so that if we did not will it, we should not do it; we should even do the contrary if we willed it." And another: "A power to do or forbear an action, according to the determination or thought of the mind, whereby either is preferred to the other." [Locke] On all which definitions, if the reader will be pleased to reflect, he will see them to be only definitions of Liberty or Freedom from outward impediments of action, and not a Freedom or Liberty from Necessity; as I also will show them to be in the sequel of this discourse, wherein I shall contend equally with them for such a power as they describe, though I affirm that there is no Liberty from Necessity.

Alexander the Apbrodissean (a most acute philosopher of the second century, and the earliest commentator now extant upon Aristotle, and esteemed his best defender and interpreter) defines Liberty to be "A power to choose what to do after deliberation and consultation, and to choose and do what is most eligible to our reason; whereas otherwise we should follow our fancy." Now a choice after deliberation, is a no less necessary choice than a choice by fancy. For though a choice by fancy, or without deliberation, may be one way, and a choice with deliberation may be another way, or different; yet each choice being founded on what is judged best, the one for one reason and the other for another, is equally necessary; and good or bad reasons, hasty or deliberate thoughts, fancy or deliberation, make no difference.

In the same manner Bishop Bramhal1, who has written several books for Liberty, and pretends to assert the Liberty taught by Aristotle, defines Liberty thus: He says, "That act which makes a man's actions to be truly free, is election; which is the deliberate choosing or refusing of this or that means, or the acception of one means before another, where divers are represented by the understanding." And that this definition places Liberty wholly in choosing the seeming best means, and not in choosing the seeming worst means, equally with the best, will appear from the following passages. He says, "Actions done in sudden and violent passions, are not free: because there is no deliberation nor election. To say the will is determined by motives, that is, by reasons or discourses, is as much as to say that the agent is determined by himself or is free. Because motives determine not naturally but morally; which kind of determination is consistent with true Liberty.

Actions "determined " by the strongest motive are not therefore pre-determined from before deliberations began.

Admitting that the will follows necessarily the last dictate of the understanding, this is not destructive of the Liberty of the will; this is only an hypothetical necessity." So that Liberty with him consists in choosing or refusing necessarily after deliberation; which choosing or refusing is morally and hypothetically determined, or necessary by virtue of the said deliberation.

Lastly, a great Armenian theologer [Le Clerc], who has writ a course of Philosophy and entered into several controversies on the subject of Liberty, makes Liberty to consist in " an indifferency of mind while a thing is under deliberation." "For;" says he, "while the mind deliberates it is free till the moment of action; because nothing determines it necessarily to act or not to act." Whereas when the mind balances or compares ideas or motives together, it is then no less necessarily determined to a state of indifferency by the appearances of those ideas and motives, than it is necessarily determined in the very moment of action. Were a man to be at liberty in this state of indifferency he ought to have it in his power to be not indifferent, at the same time that he is indifferent.

If experience therefore proves the Liberty contended for by the foregoing asserters of Liberty, it proves men to have no Liberty from Necessity.

(A Philosophical Inquiry Concerning Human Liberty, pp. 27-28. Google Scholar)

Collins then lays out his argument why why our actions are necessitated, and that there is libertarian freedom of the will is impossible.

Willing is ... matter of daily experience that we begin or forbear, continue or end, several actions barely by a thought, or preference of the mind, ordering the doing or not doing, the continuing or ending, such or such actions. Thus, before we think or deliberate on any subject, as before we get on horseback, we do prefer those things to anything else in competition with them. In like manner, if we forbear these actions when any of them are offered to our thoughts, or if we continue to proceed in any one of these actions once begun, or if at any time we make an end of prosecuting them, we do forbear, or continue, or end them on our preference of the forbearance to the doing of them, of the continuing of them to the ending them, and of the ending to the continuing them. This power of the man thus to order the beginning or forbearance, the continuance or ending of any action, is called the will, and the actual exercise thereof willing.

There are two questions usually put about this matter - first, Whether we are at liberty to will or not to will? secondly, Whether we are at liberty to will one or the other of two or more objects?

1. As to the first, whether we are at liberty to will or not to will, it is manifest we have not that liberty. For let an action in a man's power be proposed to him as presently to be done, as for example, to walk - the will to walk or not to walk exists immediately. And when an action in a man's power is proposed to him to be done to-morrow, as to walk to-morrow, he is no less obliged to have some immediate will. He must either have a will to defer willing about the matter proposed, or he must will immediately in relation to the thing proposed, and one or the other of those wills must exist immediately, no less than the will to walk or not to walk in the former case. Wherefore, in every proposal of something to be done which is in a man's power to do, he cannot but have some immediate will.

Hence appears the mistake of those [e.g., Locke] who think men at liberty to will, or not to will, because, say they, they can suspend willing, in relation to actions to be done to-morrow; wherein they plainly confound themselves with words. For when it is said man is necessarily determined to will, it is not thereby understood that he is determined to will or choose one out of two objects immediately in every case proposed to him (or to choose at all in some cases - as whether he will travel into France or Holland), but that on every proposal he must necessarily have some will. And he is not less determined to will, because he does often suspend willing or choosing in certain cases; for suspending to will is itself, an act of willing; it is willing to defer willing about the matter proposed. In fine, though great stress is laid on the case of suspending the will to prove Liberty, yet there is no difference between that and the most common cases of willing and choosing upon the manifest excellency of one object before another. For, as when a man wills or chooses living in England before going out of it (in which will he is manifestly determined by the satisfaction he has in living in England) he rejects the will to go out of England; so a man who suspends a will about any matter, wills doing nothing in it at present, or rejects for a time willing about it; which circumstances of wholly rejecting, and rejecting for a time, make no variation that affects the question. So that willing, or choosing suspension, is like all other choices or wills that we have.

2. Secondly, let us now see whether we are at liberty to will or choose one or the other of two or more objects. Now as to this we will first consider whether we are at liberty to will one of two or more objects wherein we discern any difference; that is, where one upon the whole seems less hurtful than another. And this will not admit of much dispute, if we consider what willing is.. Willing or preferring is the same with respect to good and evil, that judging is with respect to truth or falsehood. It is 'judging that one thing is, upon the whole, better than another, or not so bad as another. Wherefore, as we judge of truth or falsehood according to appearances, so we must will or prefer as things seem to us, unless we can lie to ourselves, and think that to be worst which we think best.

An ingenious author [Locke] expresses this matter well when he says, "the question whether a man be at liberty to will which of the two he pleases, motion or rest, carries the absurdity of it so manifestly in itself that one might hereby be sufficiently convinced that Liberty concerns not the will. For to ask whether a man be at liberty to will either motion or rest, speaking or silence, which he pleases, is to ask whether a man can will what he wills, or be pleased with what he is pleased with. A question that needs no answer"

To suppose a sensible being capable of willing or preferring (call it as you please) misery and refusing good, is to deny it to be really sensible; for every man while he has his senses, aims at pleasure and happiness, and avoids pain and misery; and this, in willing actions, which are supposed to be attended with the most terrible consequences. And therefore the ingenious Mr. Norris very justly observes, that all who commit sin, think it at the instant of commission, all things considered, a lesser evil; otherwise it is impossible they should commit it; and he instances in St. Peter's denial of his master, who he says, "judged that part most eligible which he choose, that is, judged the sin of denying his master, at that present juncture, to be a less evil than the danger of not denying him; and so chose it. Otherwise, if he had then actually thought it a greater evil, all that whereby it exceeded the other, he would have chosen gratis, and consequently have willed evil as evil, which is impossible." And another acute philosopher [Bayle] observes, that there are in France many new converts, who go to mass with great reluctance. They know they mortally offend God, but as each offence would cost them (suppose) two pistoles, and having reckoned the charge, and finding that this fine, paid as often as there are festivals and Sundays would reduce them and their families to beg their bread, they conclude it is better to offend God than beg.

In fine, though there is hardly anything so absurd, but some ancient philosopher or other may be cited for it; yet, according to Plato, none of them were so absurd as to say that men did evil voluntarily; and he asserts that it is contrary to the nature of man to follow evil as evil, and not pursue good; and that when a manic compelled to choose between two evils, you will never find a man who chooses the greatest, if it is in his power to choose the less; and that this is a truth manifest to all. And even the greatest modern advocates for Liberty allow that whatever the will chooseth, it chooseth under the notion of good; and that the object of the will is good in general, which is the end of all human actions.

This I take to be sufficient to show that man is not at liberty to will one or the other of two or more objects between which (all things considered) he perceives a difference; and to account truly for all the choices of that kind which can be assigned.

Collins goes on to deny even the ancient liberty of indifference.

But, secondly, some of the patrons of Liberty contend that we are free in our choice among things indifferent, or alike, as in choosing one out of two or more eggs; and that in such cases the man, having no motives from the objects, is not necessitated to choose one rather than the other, because there is no perceivable difference between them, but chooses one by a mere act of willing without any cause but his own free act.[Bramhall]

To which I answer, (1) first, by asking whether this and other instances like this are the only instances wherein man is free to will or choose among objects? If they are the only instances where man is free to will or choose among objects, then we are advanced a great way in the question; because there are few (if any) objects of the will that are perfectly alike; and because Necessity is hereby allowed to take place in all cases where there is a perceiveable difference in things, and consequently in all moral and religious cases, for the sake whereof such endeavors have been used to maintain so absurd and inconsistent a thing as Liberty or Freedom from Necessity. So that Liberty is almost, if not quite, reduced to nothing and destroyed, as to the grand end in asserting it. If those are not the only instances wherein man is free to will or choose among objects, but man is free to will in other cases, these other cases should be assigned, and not such cases as are of no consequence, and which by the great likeness of the objects to one another, and for other reasons, make the cause of the determination of man's will less easy to be known, and consequently serve to no other purpose but to darken the question, which may be better determined by considering, whether man he free to will or not in more important instances.

2. Secondly, I answer, that whenever a choice is made, there can be no equality of circumstances preceding the choice. For in the case of choosing one out of two or more eggs, between which there is no perceivable difference; there is not, nor can there be, a true equality of circumstances and causes preceding the act of choosing one of the said eggs. It is not enough to render things equal to the will, that they are equal or alike in themselves. All the various modifications of the man, his opinions, prejudices, temper, habit, and circumstances, are to be taken in, and considered as causes of election, no less than the objects without us among which we choose; and these will ever incline or determine our wills, and make the choice we do make preferable to us, though the external objects of our choice are ever so much alike to each other. And, for example, in the case of choosing one out of the two eggs that are alike, there is first, in the person choosing, will to eat or use an egg. There is, secondly, a will to take but one, or one first. Thirdly, consequent to these two wills, follow in the same instant choosing and taking one; which one is chosen and taken, most commonly, according as the parts of our bodies have been formed long since by our wills, or by other causes, to an habitual practice, or as those parts are determined by some particular circumstances at that time. And we may know, by reflection on our actions, that several of our choices have been determined to one among several objects by these last means, when no cause has arisen from the mere consideration of the objects themselves. For we know by experience that we either use all the parts of our bodies by habit, or according to some particular cause determining their use at that time.

(A Philosophical Inquiry Concerning Human Liberty, pp. 37-43. Google Scholar)

Collins asks about the presumed liberty of humans, compared with the animals, and since children are thought to have no liberty until a certain age, how does that come about?

Manuel Vargas still asks this question in the 21st century. Children and animals both have behavioral freedom. Their actions are not pre-determined. The proper question is at what age they become morally responsible

To what age do children continue necessary agents, and when do they become free? What different experience have they when they are supposed to be free agents from what they had while necessary agents? And what different actions do they do from whence it appears that they are necessary agents to a certain age, and free agents afterwards?

(A Philosophical Inquiry Concerning Human Liberty, p. 47. Google Scholar)

Collins now argues for necessity based on the impossibility of liberty, since every event has a cause, and all causes are necessary. The idea of an uncaused event (a causa suiis not only absurd but atheistical, he says.

Second argument taken from the impossibility of Liberty.

II. A second reason to prove man a necessary agent is because all his actions have a beginning. For whatever has a beginning must have a cause, and every cause is a necessary cause.

If anything can have a beginning which has no cause, then nothing can produce something. And if nothing can produce something, then the world might have had a beginning without a cause; which is not only an absurdity commonly charged on Atheists, but is a real absurdity in itself.

Besides, if a cause be not a necessary cause, it is no cause at all. For if causes are not necessary causes, then causes are not suited to, or are indifferent to effects; and the Epicurean System of chance is rendered possible; and this orderly world might have been produced by a disorderly or fortuitous concourse of atoms; or which is all one, by no cause at all. For in arguing against the Epicurean system of chance, do we not say (and that justly) that it is impossible for chance ever to have produced an orderly system of things, as not being a cause suited to the effect; and that an orderly system of things which had a beginning, must have had an intelligent agentfor its cause, as being the only proper cause to that effect? All which implies that causes are suited, or have relation to some particular effects, and not toothers. And if they be suited to some particular effect and not to others, they can be no causes at all to those others. And therefore a cause not suited to the effect, and no cause, are the same thing. And if a cause not suited to the effect is no cause, then a cause suited to the effect is a necessary cause; for if it does not produce the effect, it is not suited to it, or is no cause at all of it.

Liberty therefore, or a power to act or not to act, to do this is another thing under the same causes, is an impossibility and atheistical.

(A Philosophical Inquiry Concerning Human Liberty, p. 47. Google Scholar)

And as Liberty stands and can only be grounded on the absurd principle of Epicurean Atheism, so the Epicurean Atheists, who were the most popular and most numerous sect of the Atheists of antiquity, were the great asserters of Liberty; as on the other side the Stoics, who were the most popular and most numerous sect among the religionaries of antiquity, were the great asserters of Fate and Necessity. The case was also the same among the Jews, as among the heathen; the Jews, I say, who besides the light of nature, had many books of Revelation (some whereof are now lost) and who had intimate and personal conversation with God himself. They were principally divided into three sects, the Sadducees, the Pharisees, and the Essenes. The Sadducees, who were esteemed an irreligious and atheistical sect, maintained the liberty of man. But the Pharisees, who were a religious sect, ascribed all things to fate, or to God's appointment, and it was the first article of their creed that fate and God do all; and consequently they do not assert a true liberty, when they asserted a liberty together with this fatality and necessity of all things. And the Essenes, who were the most religious sect among the Jews, and fell not under the censure of our Savior for their hypocrisy as the Pharisees did, were asserters of absolute fate and necessity. St. Pau1, who was a Pharisee, and the son of a Pharisee, is supposed by the learned Dodwell, to have received his doctrine of fate from the masters of that sect, as they received it from the Stoics. And he observes further, that the Stoic philosophy is necessary for the explication of Christian theology; that there are examples in the holy scriptures of the Holy Ghost's speaking according to the opinions of the Stoics, and that in particular the apostle St. Paul in what he has disputed concerning predestination and reprobation, is to be expounded according to the Stoics' opinion concerning fate. So that Liberty is both the real foundation of popular Atheism, and has been the professed principle of the Atheists themselves; as on the other side, Fate, or the necessity of events, has been esteemed a religious opinion and been the professed principle of the religious, both among heathens and Jews, and also of that great convert to Christianity and great converter of others, St. Pau1.

(A Philosophical Inquiry Concerning Human Liberty, pp. 48-50. Google Scholar)

The perfection of Necessity.

But the imperfection of Liberty inconsistent with Necessity will yet more appear by considering the great perfection of being necessarily determined.

Can anything be perfect that is not necessarily perfect I For whatever is not necessarily perfect may be imperfect, and is by consequence imperfect.

Is it not a perfection in God necessarily to know all truth?

Is it not a perfection in him to be necessarily happy ?

Is it not also a perfection in him to will and do always what is best? For if all things are indifferent to him, as some of the advocates of Liberty assert [King], and become good only by his willing them, he cannot have any motive from his own ideas, or from the nature of things, to will one thing rather than another, and consequently he must will without any reason or cause, which cannot be conceived possible of any being, and is contrary to this self-evident, truth that whatever has a beginning must have a cause. But if things are not indifferent to him, he must be necessarily determined by what is best. Besides, as he is a wise being, he must have some end and design, and as he is a good being, things cannot be indifferent to him, when the happiness of intelligent and sensible beings depend on the will he has in the formation of things. With what consistency, therefore, can those advocates of Liberty assert God to be a holy and good being, who maintain that all things are indifferent to him before he wills anything, and that he may will and do all things which they themselves esteem wicked and unjust?

(A Philosophical Inquiry Concerning Human Liberty, pp. 48-50. Google Scholar)

Are not angels and other heavenly beings esteemed more perfect than men; because, having a clear insight into the nature of things, they are necessarily determined to judge right in relation to truth and falsehood, and to choose right in relation to good and evil, pleasure and pain; and also to act right in pursuance of their judgment and choice? And therefore would not man be more perfect than he is, if, by having a clear insight into the nature of things, he was necessarily determined to assent to truth only, to choose only such objects as would make him happy, and to act accordingly?

Further, is not man more perfect the more capable he is of conviction? And will he not be more capable of conviction if he be necessarily determined in his assent by what seems a reason to him, and necessarily determined in his several volitions by what seems good to him, than if he was indifferent to propositions, notwithstanding any reason for them, or was indifferent to any objects, notwithstanding they seemed good to him? for otherwise he could be convinced upon no other principles, and would be the most undisciplinable and untractable of all animals. All advice and all reasonings would be of no use to him. You might offer arguments to him, and lay before him pleasure and pain; and he might stand unmoved like a rock. He might reject what appears true to him, assent to what seems absurd to him, avoid what he sees to be good, and choose what he sees to be evil. Indifference therefore to receive truth, that is Liberty to deny it when we see it; and indifference to pleasure and pain, that is, Liberty to refuse the first, and choose the last; are direct obstacles to knowledge and happiness. On the contrary, to be necessarily determined by what seems reasonable, and by what seems good, has a direct tendency to promote truth and happiness, and is the proper perfection of an understanding and sensible being. And indeed it seems strange that men should allow that God and angels act more perfectly because they are determined by reason; and also allow that clocks, watches, mills, and other artificial unintelligent beings are the better, the more they are determined to go right by weight and measure; and yet that they should deem in a perfection in man not to be determined by his reason, but to have Liberty to go against it. Would it not be as reasonable to say it would be a perfection in a clock not to be necessarily determined to go right, but to have its motions depend upon chance?

(A Philosophical Inquiry Concerning Human Liberty, p. 59. Google Scholar)

My sixth and last argument to prove man a necessary agent is; if man was not a necessary agent determined by pleasure and pain, he would have no notion of morality, or motive to practise it; the distinction between morality and immorality, virtue and vice, would be lost; and man would not be a moral agent.

Morality or Virtue, consists of such actions as are in their own nature, and upon the whole pleasant; and immorality or vice, consists in such actions as are in their own nature, and upon the whole painful. Wherefore a man must be affected with pleasure and pain in order to know what morality is, and to distinguish it from immorality. He must also be affected with pleasure and pain to have a reason to practise morality; for there can be no motives but pleasure and pain to make a man do or forbear any action. And a man must be the more moral the more he understands or is duly sensible, what actions give pleasure and what pain; and must be perfectly moral if necessarily determined by pleasure and pain rightly understood and apprehended. But if man be indifferent to pleasure and pain, or is not duly affected with them, he cannot know what morality is nor distinguish it from immorality, nor have any motive to practise morality and abstain from immorality; and will be equally indifferent to morality and immorality or virtue and vice. Man in his present condition is sufficiently immoral by mistaking pain for pleasure and thereby judging, willing, and practising amiss; but if he was indifferent to pleasure and pain, he would have no rule to go by, and might never judge, will, and practise right.

Though I conceive I have so proposed my arguments as to have obviated most of the plausible objections- usually urged against the doctrine of Necessity, yet it may not be improper to give a particular solution to the principal of them.

1. First then it is objected that if men are necessary agents,9 and do commit necessarily all breaches of the law, it would be unjust to punish them fordoing what they cannot avoid doing.

To which I answer that the sole end of punishment in society is to prevent, as far as may be, the commission of certain crimes; and that punishments have their designed effect two ways; first, by restraining or cutting off from society the vicious members; and secondly, by correcting men or terrifying them from the commission of those crimes. Now let punishments be inflicted with either of these views, it will be manifest that no regard is had to any free agency in man, in order to render those punishments just; but that on the contrary, punishments may be justly inflicted on man, though a necessary agent. For, first, if murderers for example, or any such vicious members are cut off from society, merely as they are public nuisances and unfit to live among men; it is plain they are in that case so far from being considered as free agents that they are cut off from society as a cankered branch is from a tree, or as a mad dog is killed in the streets. And the punishment of such men is just, as it takes mischievous members out of society. Also, for the same reason, furious madmen, whom all allow to be necessary agents, are in many places of the world either the objects of judicial punishments, or be allowed to be dispatched by private men. Nay, even men infected with the plague, who are not voluntary agents and are guilty of no crime, are sometimes thought to be justly cut off from society to prevent contagion from them.

Secondly, let punishments be inflicted on some criminals with a view to terrify, it will appear that in inflicting punishments with that view, no regard is had to any free agency in man in order to make those punishments just. To render the punishment of such men just, it is sufficient that they were voluntary agents, or had the will to do the crime for which they suffer, for the law very justly and rightly regardeth only the will, and no other preceding causes of action. For example, suppose the law, on pain of death, forbids theft, and there be a man who, by the strength of temptation, is necessitated to steal, and is thereupon put to death for it; doth not his punishment deter others from theft? Is it not a cause that others steal not? doth it not frame their wills to justice? Whereas a criminal who is an involuntary agent (as for instance a man who has killed another in a chance medly, or while in a fever or the like) cannot serve for an example to deter any others from doing the same, he being no more an intelligent agent in doing the crime than a house is which kills a man by its fall, and by consequence the punishment of such an involuntary agent would be unjust. When therefore a man does a crime voluntarily, and his punishment will serve to deter others from doing the same, he is justly punished for doing what (through strength of temptation, ill habits, or other causes) he could not avoid doing.

It may not be improper to add this farther consideration from the law of our country. There is one case wherein our law is so far from requiring that the persons punished should be free agents, that it does not consider them as voluntary agents, or even as guilty of the crime for which they suffer: so little is free agency requisite to make punishments just. The children of rebel parents suffer in their fortunes for the guilt of their parents, and their punishment is deemed just, because it is supposed to be a means to prevent rebellion in parents.

II. Secondly, it is objected that it is useless to threaten punishment, or inflict it on men to prevent crimes, when they are necessarily determined in all their actions.

1. To which I answer first, that threatening of punishments is a cause which necessarily determines some men's wills to a conformity to law, and against committing the crimes to which punishments are annexed, and therefore is useful to all those whose wills must be determined by it. It is as useful to such men, as the sun is to the ripening the fruits of the earth, or as any other causes are to produce their proper effects, and a man may as well say the sun is useless, if the ripening the fruits of the earth be necessary, as say there is no need of threatening punishment for theuse of those to whom threatening punishment is a necessary cause of forbearing to do a crime. It is also of use to society to inflict punishments on men for doing what they cannot avoid doing, to the end that necessary causes may exist to form the wills of those who in virtue of them necessarily observe the laws, and also of use to cut them off as noxious members of society.

(A Philosophical Inquiry Concerning Human Liberty, pp. 63-67. Google Scholar)