Aquinas Rejects Determinism

This post is taken from Thomas Aquinas, On Human Choice, and is the Disputed Question on Evil, 6 (1266-72). He notes arguments for and against free will and then responds. I will briefly quote from each section and include footnotes. The editor and translator, Ralph McInerny, constructs an introduction, noted in italics, then Aquinas writes the following.


The will is a rational appetite, that is, a desire consequent upon knowledge. What specifies and individutates will-acts is the cognitive content that gives them direction. This is why reason is called the formal cause of willing; it specifies willing and gives it direction. But will as efficient cause can move mind and other human faculties. We choose to think or not to think about this or that [contrary to Calvin].

Now it might be thought that once mind has specified an object for will, put before it, so to speak, something as good, fulfilling and perfective, the will must necessarily desire that good. What assures the freedom of the will is not that appetite can . . . opt for something unthought of -- a concept of will that has led many to deny that Aristotle had a concept of will. 

Rather, whatever particular good the mind puts forward as specifying the will falls short of goodness itself [an argument Arminius constantly affirmed]. That is, any proposed object of will is a mixed case, comprising negative as well as positive aspects. Because of the inadequacy as good of any object proposed to the will, the will is free in its regard. . . .

In the text below, Thomas drives the analysis back to this basic act of the will, its desire for goodness as such. The will is precisely an appetite for goodness. When reason proposes an object to will, this orientation to the good as such is presupposed. Everything we choose must be made to fit under the formality of goodness, that is, be presented as something perfective and fulfilling of us. 

Considered as a nature, it is of the essence of will to seek goodness itself. The cause of this is the cause of the will’s nature, God. Does God’s causality negate freedom? The following text is rightly considered to be Thomas’s most thorough discussion of this question.1



Does a man have free choice in his actions or does he choose necessarily?

It seems that he chooses necessarily, not freely [is the argument offered].

1. For it is said in Jeremiah 10:23 “that the way of a man is not his, neither is it in a man to walk and direct his steps”. But that with respect to which a man has freedom is his, as constituted, as it were, within his dominion. Therefore, it seems that a man does not have free choice of his way or of his acts.

2. It might be objected that this does not refer to the execution of choice, which sometimes is not within a man’s power. On the contrary, there is what the Apostle says in Romans 9:16: “So then there is the question not of him who wills or him who runs, but of God showing mercy”. But running pertains to the external execution of acts and willing to the interior choice. Therefore, not even interior choices are in man’s power, but are in man from God.

3. But it will be said that a man is moved to choice by an inner instinct, namely by God himself, and immovably and that this is not repugnant to freedom. On the contrary, any animal moves himself through appetite, but animals other than man do not have free choice because their appetite is moved by some external agent, for example the power of a heavenly body or by the action of some other body. Therefore, if man’s will is immovably moved by God, it would follow that a man does not have free choice in his actions. . . .

5. Moreover, it is impossible for man’s will to be out of harmony with the will of God because, as Augustine says in the Enchiridion, either man does what God wills or God fulfills his will concerning him. But God’s will is immutable. Therefore, man’s will is too. Therefore, all human choices proceed from an unchangeable choice. . . .2


1. There is what is said in Ecclesiasticus 15:14: “God made man from the beginning, and left him in the hand of his own counsel.” This would not be so if he did not have free choice, which is the desire of what has been previously deliberated about, as is said in Ethics 3. Therefore, man has free choice in his actions.

2. Moreover, rational powers are ordered to opposites, according to the Philosopher, and will is a rational power, for it resides in reason, as is said in On the Soul 3. Therefore, will is related to opposites and is not necessarily moved to one thing.

3. Moreover, according to the Philosopher in Ethics 3, a man is lord of his acts and he has it in him to act and not to act. But this would not be if he did not have free choice in his acts.3


It should be noted that some held that man’s will is necessarily moved to choose something, although they did not say that the will was forced. For not every necessary event is violent, but only that whose principle is from without; hence there are some natural motions which are necessary but not violent: the violent is opposed to both the natural and the voluntary, each of which has its principle within, whereas the principle of the violent is from without.

But this is a heretical opinion, for it takes away the very notion of merit and demerit from human acts. For what someone does necessarily, and cannot avoid doing, seems to be neither meritorious nor the opposite. Therefore,  this should be numbered among the opinions alien to philosophy, since not only is it contrary to faith but it subverts all the principles of moral philosophy as well. 

If there is nothing free in us, but we are moved to will necessarily, deliberation, exhortation, precept and punishment, praise and blame, in which moral philosophy consists, are swept away. Such opinions, which destroy the principles of some part of philosophy, are called alien positions: for example, “Nothing moves,” which destroys the principles of natural science. Some men were led to adopt such positions partly from stupidity and partly because of sophistic arguments which they were unable to solve, as is said in Metaphysics 4.

To get to the truth of this matter we must first consider that just as in other things there is a principle of their proper activity, so too is there in man. In man intellect and will are the proper active and moving principle, as is said in On the Soul 3. This principle is in some ways like the active principle of natural things and in some ways unlike.

Alike, indeed, because just as in natural things there is a form that is the principle of action, and an inclination following form, which is called natural appetite, on which action follows, so in man there is an intellective form and the ensuing inclination of will according to the form apprehended, on which the external act follows. But there is this difference, that the form and the natural thing is individuated by matter so that the inclination following it is determined to one, but the understood form is universal and comprises many within it. Hence, since actions are singular and are not equal to a universal power, the inclination of will is indeterminately related to many. Just as when the artisan conceives the general form of house, under which are included different shapes of houses, his will can be inclined to make a square house or a round one or one of another shape. . . .

Second, it should be noticed that any power is moved in two ways: in one way, on the part of the subject; in another, on the part of the object. On the part of the subject, as sight sees more or less clearly because of a change in disposition of its origin; on the part of the object, as sight sees now white, now black. The first change pertains to the exercise of the act, namely that one should act or not act, for an act is specified by its object. . . .4

Well then, in order to show that the will is not moved with necessity, we must consider the movement of will both with respect to the exercise and with respect to the determination of its act, which is from the object. With respect to the exercise of it first, it is first of all manifest that the will is moved by itself, for just as it moves other powers, so does it move itself. 

Nor does it follow from this that the will is simultaneously potential and actual, for just as a man in understanding moves himself to knowledge in the mode of discovery, insofar as from one actually known thing he goes on to something unknown, which is known only potentially, so by the fact that a man actually wills something, he moves himself actually to will something else; for example, because he wills health, he moves himself to want to take his medicine. From the fact that he wants health, he begins to deliberate about what health requires and having fixed on it by deliberation, he wants to take the medicine.

Deliberation, therefore, precedes the will to take medicine, which in turn proceeds from one’s will to deliberate. And since the will moves itself to deliberation, and deliberation is a kind of non-demonstrative inquiry, open to opposites, the will does not move itself necessarily. And since the will does not always will to deliberate, it must be moved by something to want to deliberate, and if by itself, it is necessary that deliberation precede that movement of will and that an act of will precede deliberating. 

Since this cannot be an infinite regress, it must be acknowledged that, with respect to the first movement of the will, the will of anyone not always actually willing is moved by something outside, by whose instigation the will begins to will. . . .So, then, with respect to some things the will is necessarily moved on the side of the object, but not with respect to everything, but on the side of exercise of its act it is not moved necessarily. . . .6

It should be said that man's will is discordant with the will of God insofar as it wills something God does not want it to will, as when it wills to sin; though God does not want it to will, as when it wills to sin; though God does not want the will to will this, if it so wills God brings it about, for whatever it wills the Lord does. And though in this way man’s will is discordant with the will of God with respect to the movement of will, it can never be discordant with respect to result or event, for a man’s will always chooses that event because God always fulfills his will concerning man. But with respect to the manner of willing it is not necessary that man’s will be conformed to God’s, because God wills whatever he wills eternally and infinitely, but man does not. Because of this, it is said in Isaiah 55:9, "For as the heavens are exalted above the earth, so are my ways exalted above your ways."7


1 Thomas Aquinas: Selected Writings, ed. and trans. Ralph McInerny (New York: Penguin Books, 1998), 4.22551-52.

2 Ibid., 4.22.552.

3 Ibid., 4.22.556.

4 Ibid., 4.22.556-57.

5 Ibid., 4.22.559-60.

6 Ibid., 4.22.560.

7 Ibid., 4.22.561.