I think the question is not proper, whether the will be free, but whether a man be free. (Book II, Chapter XXI, Of Power, s.21)

He pursues the question further. Are we free to will what we will? This Locke argues leads to an infinite regress.

Concerning a man's liberty, there yet, therefore, is raised this further question, Whether a man be free to will? which I think is what is meant, when it is disputed whether the will be free. (s.22)

...to make a man free after this manner, by making the action of willing to depend on his will, there must be another antecedent will, to determine the acts of this will, and another to determine that, and so in infinitum: for wherever one stops, the actions of the last will cannot be free. (s.23)

This, then, is evident, That a man is not at liberty to will, or not to will, anything in his power...: liberty consisting in a power to act or to forbear acting, and in that only. (s.24)

In two-stage models of free will, the first "free" stage simply generates alternative possibilities for thoughts and actions. The second "willed" stage can be adequately determined to perform or forbear any action for reasons, motives, feelings, etc.

5. This, at least, I think evident, — That we find in ourselves a power to begin or forbear, continue or end several actions of our minds, and motions of our bodies, barely by a thought or preference of the mind ordering, or as it were commanding, the doing or not doing such or such a particular action. This power which the mind has thus to order the consideration of any idea, or the forbearing to consider it; or to prefer the motion of any part of the body to its rest, and vice versa, in any particular instance, is that which we call the Will. The actual exercise of that power, by directing any particular action, or its forbearance, is that which we call volition or willing. The forbearance of that action, consequent to such order or command of the mind, is called voluntary. And whatsoever action is performed without such a thought of the mind, is called involuntary.

7. Every one, I think, finds in himself a power to begin or forbear, continue or put an end to several actions in himself. From the consideration of the extent of this power of the mind over the actions of the man, which everyone finds in himself, arise the ideas of liberty and necessity.

8. So far as a man has power to think or not to think, to move or not to move, according to the preference or direction of his own mind, so far is a man free. Wherever any performance or forbearance are not equally in a man's power; wherever doing or not doing will not equally follow upon the preference of his mind directing it, there he is not free, though perhaps the action may be voluntary. So that the idea of liberty is, the idea of a power in any agent to do or forbear any particular action, according to the determination or thought of the mind, whereby either of them is preferred to the other: where either of them is not in the power of the agent to be produced by him according to his volition, there he is not at liberty; that agent is under necessity. So that liberty cannot be where there is no thought, no volition, no will; but there may be thought, there may be will, there may be volition, where there is no liberty. A little consideration of an obvious instance or two may make this clear.

9. A tennis-ball, whether in motion by the stroke of a racket, or lying still at rest, is not by any one taken to be a free agent. If we inquire into the reason, we shall find it is because we conceive not a tennis-ball to think, and consequently not to have any volition, or preference of motion to rest, or vice versa; and therefore has not liberty, is not a free agent; but all its both motion and rest come under our idea of necessary, and are so called. Likewise a man falling into the water, (a bridge breaking under him,) has not herein liberty, is not a free agent. For though he has volition, though he prefers his not falling to falling; yet the forbearance of that motion not being in his power, the stop or cessation of that motion follows not upon his volition; and therefore therein he is not free. So a man striking himself, or his friend, by a convulsive motion of his arm, which it is not in his power, by volition or the direction of his mind, to stop or forbear, nobody thinks he has in this liberty; every one pities him, as acting by necessity and constraint.

The original of a Frankfurt example where an apparent alternate possibilty does not exist

10 Again: suppose a man be carried, whilst fast asleep, into a room where is a person he longs to see and speak with; and be there locked fast in, beyond his power to get out: he awakes, and is glad to find himself in so desirable company, which he stays willingly in, i.e. prefers his stay to going away. I ask, is not this stay voluntary? I think nobody will doubt it: and yet, being locked fast in, it is evident he is not at liberty not to stay, he has not freedom to be gone. So that liberty is not an idea belonging to volition, or preferring; but to the person having the power of doing, or forbearing to do, according as the mind shall choose or direct. Our idea of liberty reaches as far as that power, and no farther. For wherever restraint comes to check that power, or compulsion takes away that indifferency of ability to bear acting, there liberty, and our notion of it, presently ceases.

13. Wherever thought is wholly wanting, or the power to act or forbear according to the direction of thought, there necessity takes place. This, in an agent capable of volition, when the beginning or continuation of any action is contrary to that preference of his mind, is called compulsion; when the hindering or stopping any action is contrary to his volition, it is called restraint. Agents that have no thought, no volition at all, are in everything necessary agents.

Freedom of the Will unintelligible

14. If this be so, (as I imagine it is,) I leave it to be considered, whether it may not help to put an end to that long agitated, and, I think, unreasonable, because unintelligible question, viz. Whether man's will be free or no? For if I mistake not, it follows from what I have said, that the question itself is altogether improper; and it is as insignificant to ask whether man's will be free, as to ask whether his sleep be swift, or his virtue square: liberty being as little applicable to the will, as swiftness of motion is to sleep, or squareness to virtue. Every one would laugh at the absurdity of such a question as either of these: because it is obvious that the modifications of motion belong not to sleep, nor the difference of figure to virtue; and when any one well considers it, I think he will as plainly perceive that liberty, which is but a power, belongs only to agents, and cannot be an attribute or modification of the will, which is also but a power.

15. Such is the difficulty of explaining and giving clear notions of internal actions by sounds, that I must here warn my reader, that ordering, directing, choosing, preferring, &c., which I have made use of, will not distinctly enough express volition, unless he will reflect on what he himself does when he wills. For example, preferring, which seems perhaps best to express the act of volition, does it not precisely. For though a man would prefer flying to walking, yet who can say he ever wills it? Volition, it is plain, is an act of the mind knowingly exerting2 that dominion it takes itself to have over any part of the man, by employing it in, or withholding it from, any particular action. And what is the will, but the faculty to do this?

Depends on us - the classical ἐφ ἡμῖν

And is that faculty anything more in effect than a power; the power of the mind to determine its thought, to the producing, continuing, or stopping any action, as far as it depends on us? For can it be denied that whatever agent has a power to think on its own actions, and to prefer their doing or omission either to other, has that faculty called will? Will, then, is nothing but such a power. Liberty, on the other side, is the power a man has to do or forbear doing any particular action according as its doing or forbearance has the actual preference in the mind; which is the same thing as to say, according as he himself wills it.

16. It is plain then that the will is nothing but one power or ability, and freedom another power or ability - so that, to ask, whether the will has freedom, is to ask whether one power has another power, one ability another ability; a question at first sight too grossly absurd to make a dispute, or need an answer. For, who is it that sees not that powers belong only to agents, and are attributes only of substances, and not of powers themselves? So that this way of putting the question (viz. whether the will be free) is in effect to ask, whether the will be a substance, an agent, or at least to suppose it, since freedom can properly be attributed to nothing else. If freedom can with any propriety of speech be applied to power, it may be attributed to the power that is in a man to produce, or forbear producing, motion in parts of his body, by choice or preference; which is that which denominates him free, and is freedom itself. But if any one should ask, whether freedom were free, he would be suspected not to understand well what he said; and he would be thought to deserve Midas's ears, who, knowing that rich was a denomination for the possession of riches, should demand whether riches themselves were rich.

18. This way of talking, nevertheless, has prevailed, and, as I guess, produced great confusion.

21. To return, then, to the inquiry about liberty, I think the question is not proper, whether the will be free, but whether a man be free. Thus, I think,

First, That so far as any one can, by the direction or choice of his mind, preferring the existence of any action to the non-existence of that action, and vice versa, make it to exist or not exist, so far he is free. For if I can, by a thought directing the motion of my finger, make it move when it was at rest, or vice versa, it is evident, that in respect of that I am free: and if I can, by a like thought of my mind, preferring one to the other, produce either words or silence, I am at liberty to speak or hold my peace: and as far as this power reaches, of acting or not acting, by the determination of his own thought preferring either, so far is a man free. For how can we think any one freer, than to have the power to do what he will? And so far as any one can, by preferring any action to its not being, or rest to any action, produce that action or rest, so far can he do what he will. For such a preferring of action to its absence, is the willing of it: and we can scarce tell how to imagine any being freer, than to be able to do what he wills. So that in respect of actions within the reach of such a power in him, a man seems as free as it is possible for freedom to make him.

22. But the inquisitive mind of man, willing to shift off from himself, as far as he can, all thoughts of guilt, though it be by putting himself into a worse state than that of fatal necessity, is not content with this: freedom, unless it reaches further than this, will not serve the turn: and it passes for a good plea, that a man is not free at all, if he be not as free to will as he is to act what he wills. Concerning a man's liberty, there yet, therefore, is raised this further question, Whether a man be free to will? which I think is what is meant, when it is disputed whether the will be free. And as to that I imagine.

23. Secondly, That willing, or volition, being an action, and freedom consisting in a power of acting or not acting, a man in respect of willing or the act of volition, when any action in his power is once proposed to his thoughts, as presently to be done, cannot be free. The reason whereof is very manifest. For, it being unavoidable that the action depending on, his will should exist or not exist, and its existence or not existence following perfectly the determination and preference of his will, he cannot avoid willing the existence or non-existence of that action; it is absolutely necessary that he will the one or the other; i.e. prefer the one to the other: since one of them must necessarily follow; and that which does follow follows by the choice and determination of his mind; that is, by his willing it: for if he did not will it, it would not be. So that, in respect of the act of willing, a man in such a case is not free: liberty consisting in a power to act or not to act; which, in regard of volition, a man, upon such a proposal has not. For it is unavoidably necessary to prefer the doing or forbearance of an action in a man's power, which is once so proposed to his thoughts; a man must necessarily will the one or the other of them; upon which preference or volition, the action or its forbearance certainly follows, and is truly voluntary. But the act of volition, or preferring one of the two, being that which he cannot avoid, a man, in respect of that act of willing, is under a necessity, and so cannot be free; unless necessity and freedom can consist together, and a man can be free and bound at once. Besides to make a man free after this manner, by making the action of willing to depend on his will, there must be another antecedent will, to determine the acts of this will, and another to determine that, and so in infinitum: for wherever one stops, the actions of the last will cannot be free. Nor is any being, as far I can comprehend beings above me, capable of such a freedom of will, that it can forbear to will, i.e. to prefer the being or not being of anything in its power, which it has once considered as such.

24. This, then, is evident, That a man is not at liberty to will, or not to will, anything in his power that he once considers of: liberty consisting in a power to act or to forbear acting, and in that only. For a man that sits still is said yet to be at liberty; because he can walk if he wills it. A man that walks is at liberty also, not because he walks or moves; but because he can stand still if he wills it. But if a man sitting still has not a power to remove himself, he is not at liberty; so likewise a man falling down a precipice, though in motion, is not at liberty, because he cannot stop that motion if he would. This being so, it is plain that a man that is walking, to whom it is proposed to give off walking, is not at liberty, whether he will determine himself to walk, or give off walking or not: he must necessarily prefer one or the other of them; walking or not walking. And so it is in regard of all other actions in our power so proposed, which are the far greater number. For, considering the vast number of voluntary actions that succeed one another every moment that we are awake in the course of our lives, there are but few of them that are thought on or proposed to the will, till the time they are to be done; and in all such actions, as I have shown, the mind, in respect of willing, has not a power to act or not to act, wherein consists liberty. The mind, in that case, has not a power to forbear willing; it cannot avoid some determination concerning them, let the consideration be as short, the thought as quick as it will, it either leaves the man in the state he was before thinking, or changes it; continues the action, or puts an end to it. Whereby it is manifest, that it orders and directs one, in preference to, or with neglect of the other, and thereby either the continuation or change becomes unavoidably voluntary.

25. Since then it is plain that, in most cases, a man is not at liberty, whether he will or no, (for, when an action in his power is proposed to his thoughts, he cannot forbear volition; he must determine one way or the other ;) the next thing demanded is, — Whether a man be at liberty to will which of the two he pleases, motion or rest? This question carries the absurdity of it so manifestly in itself, that one might thereby sufficiently be 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 which, I think, needs no answer: and they who can make a question of it must suppose one will to determine the acts of another, and another to determine that, and so on in infinitum.

26. To avoid these and the like absurdities, nothing can be of greater use than to establish in our minds determined ideas of the things under consideration. If the ideas of liberty and volition were well fixed in our understandings, and carried along with us in our minds, as they ought, through all the questions that are raised about them, I suppose a great part of the difficulties that perplex men's thoughts, and entangle their understandings, would be much easier resolved ; and we should perceive where the confused signification of terms, or where the nature of the thing caused the obscurity.

27. First, then, it is carefully to be remembered, That freedom consists in the dependence of the existence, or not existence of any action, upon our volition of it; and not in the dependence of any action, or its contrary, on our preference. A man standing on a cliff, is at liberty to leap twenty yards downwards into the sea, not because he has a power to do the contrary action, which is to leap twenty yards upwards, for that he cannot do; but he is therefore free, because he has a power to leap or not to leap. But if a greater force than his, either holds him fast, or tumbles him down, he is no longer free in that case; because the doing or forbearance of that particular action is no longer in his power. He that is a close prisoner in a room twenty feet square, being at the north side of his chamber, is at liberty to walk twenty feet southward, because he can walk or not walk it; but is not, at the same time, at liberty to do the contrary, i. e. to walk twenty feet northward.

In this, then, consists freedom, viz. in our being able to act or not to act, according as we shall choose or will.

15. Besides the complex ideas we have of material sensible substances, of which I have last spoken,— by the simple ideas we have taken from those operations of our own minds, which we experiment (experience) daily in ourselves, as thinking, understanding, willing, knowing, and power of beginning motion, etc, co-existing in some substance, we are able to frame the complex idea of an immaterial spirit. And thus, by putting together the ideas of thinking, perceiving, liberty, and power of moving themselves and other things, we have as clear a perception and notion of immaterial substances as we have of material. For putting together the ideas of thinking and willing, or the power of moving or quieting corporeal motion, joined to substance, of which we have no distinct idea, we have the idea of an immaterial spirit; and by putting together the ideas of coherent solid parts, and a power of being moved, joined with substance, of which likewise we have no positive idea, we have the idea of matter. The one is as clear and distinct an idea as the other: the idea of thinking, and moving a body, being as clear and distinct ideas as the ideas of extension, solidity, and being moved. For our idea of substance is equally obscure, or none at all, in both: it is but a supposed I know not what, to support those ideas we call accidents. It is for want of reflection that we are apt to think that our senses show us nothing but material things. Every act of sensation, when duly considered, gives us an equal view of both parts of nature, the corporeal and spiritual. For whilst I know, by seeing or hearing, etc, that there is some corporeal being without me, the object of that sensation, I do more certainly know, that there is some spiritual being within me that sees and hears. This, I must be convinced, cannot be the action of bare insensible matter: nor ever could be, without an immaterial thinking being.