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Aquinas and the Freedom of the Will

In examining human activity, one immediately supposes that people are capable of making free choices. Upon introspection, we become aware that in particular situations that we might not have acted as we in fact did or that we might not have acted at all. This contingency which we have, or at least think we have, suggests to us our freedom. Further, the fact that not all people behave the same way in the same circumstances seems to show that no one course of action is determined for these similarly disposed people. Also judging from the way we organize ourselves and relate to one another lends credence to freedom of the will. For society enacts laws prohibiting or exhorting certain behavior, belying the assumption that such behavior may or may not be performed; that people need prohibition or exhortation. All these examples are general sorts of empirical data indicating the the human will is free, at least some of the time.

These are the reasons that St. Thomas Aquinas has for supposing that people have free choice.(St. Thomas Aquinas, Summa Theologiae Ia, Q. 83, a. 1.) St. Thomas first of all believes, or rather assumes, that the will is free. Throughout his writings, however, he devotes a considerable amount of time to questions regarding this assumed freedom. By means of his philosophical approach, based principally upon Aristotle, he explains the will's freedom as being based on the nature of existing reality and the human psyche. The large amount of time he gives to the topic is to understand the generally accepted phenomenon and not to prove its veracity.

In order to understand Thomas' explanation of freedom, it would do us well to consider some difficulties involved in its analysis, difficulties stemming from our understanding (or misunderstanding) of the term. Freedom can be defined with respect to various other nebulous terms. For instance, the will is called free, but what is a will? Also, freedom is obviously opposed to the imposition of force on the person who is willing. But does this mean that free will is forced if it seeks the same kinds of things? Or for something to be voluntary, need its object be totally undetermined? Is being voluntary and free the same thing? A clarification of major concepts, then, seems to be in order.

The Will

First off, let us treat the will. Generically, the will is an appetite, that is, a power of the soul by which we are inclined toward something. By means of appetitive powers, we seek and desire things; we strive to unite ourselves (in various ways) with them. They are consequent upon knowledge. "Some inclination follows every form."( ST, Ia, 80, 1 ) Because knowledge the attainment of a new form in a non-material way, an inclination of the appetite follows upon this knowledge. So, since there are two kinds of knowledge, sense and intellectual, there are consequently two kinds of appetites.

From sense knowledge, ie. the apprehension of the forms of things in their particularity, sensual appetition follows. In a like manner, from intellectual knowledge, the apprehension of universal forms, intellectual appetition follows. In humans, the intellect is discursive, going from premises to conclusions logically, and so is called rational. Likewise the consequent appetite is rational; it is called the will. The will then is that power by which we desire the universal, not bound in itself to any manifestation of that universal in particular, real, material things.

The object of both appetites is proportionate to the kind of knowledge appropriate to that appetite. Now all appetites tend toward goodness in some manner, and the manner of tending is determined by the kind of form it has, that is the kind of knowledge. So, sense appetite tends toward sensible, particular goods, and the will toward universal goodness.


After having settled on what we mean by will, we need to consider the meaning of necessity and the consider if the any necessity in the will negates freedom. St. Thomas uses necessity to mean that which cannot be otherwise.(ST, Ia, 83, 1) In both the Summa Theologiae and De Veritate he considers it from the four causes of Aristotle: the two internal causes, material and formal, and the two external causes, efficient and final.

Internal Necessity

Necessity that arises from internal causes is considered natural necessity. For corporeal substances, the intrinsic principles of matter and form are the natural causes of the thing. That a tree is corruptible follows upon its being material, and that it is vegetative follows upon it having the form of tree. That the tree grows and dies is of natural necessity. The will is not material and so has no necessity corresponding to this kind of cause. However, the will considered as a nature, the principle of an action, the will has natural necessity following upon its nature that it is inclined toward universal goodness.(St. Thomas Aquinas, De Veritate, Q. 22, a. 5.) Of necessity the will follows upon reason, for to will anything, that thing must first be known. Likewise as a power distinct from the intellect, the will has a distinct object, the universal good as opposed to universal truth. This object is necessary according to the will being what it is.

External Necessity

Necessity can also arise from exterior causes. In the order of efficient causality, a thing is moved necessarily by an exterior agent contrary to its natural inclination.( ST Ia, 82, 1) St. Thomas uses the example of a rock which is lifted. The rock naturally tend to move down because of the kind of thing that it is. To move it upward is to oppose its natural inclination. However, the will is moved by an exterior agent as it was created, ie. to move itself to its first act of willing as opposed to not willing, and with respect to knowledge of the object of its inclination after it has been moved to will. In making a thing to be what it is, the maker is the efficient cause of its behavior and motion. So the maker of the rock is the efficient cause of the rock's fall according to natural necessity. Likewise, the maker of the will causes it to move itself. So this exterior cause is not opposed to its inclination that follows upon its nature, for it is the cause of the nature. The knowledge that moves the will to will some object is also not opposed to the nature of the will, for the will by nature is a rational power. This necessity, that is called coercion, is totally repugnant to the will.

While the will has no necessity in the order of efficient causality, the same is not true for final causality. Since the will is an appetite, it is the faculty by which we are inclined towards things. But to be inclined implies an object of inclination, that is an end. The end of the will, universal goodness, is given to it by its nature. So if this end causes necessity, it is in regard to certain means to attain that end. With respect to certain actions, crossing the ocean for instance, the will may be subject to necessity of end or utility when a particular end is attainable by only one means, eg. sailing in a ship.(DV 22.5.)

With all this discussion of necessity, our thoughts naturally turn to coercion. Coercion or force is efficient necessity against ones will. As an example, if I am thrown into a room that do not want to be in, some agent moves me against my will or inclination. As was shown above, coercive necessity is opposed to the will. It is also clear that coercion in the broader sense of being opposed to the will cannot move the will. In that case the will would be inclined to what it is not inclined, an obvious contradiction.

The Voluntary

If coercion is opposed to the will's freedom, what meaning has "voluntary?" St. Thomas takes voluntary to mean that which follows from the will. Even those things concerning the will that cannot be otherwise, necessities according to nature and finality, are voluntary.(ST Ia, 83, 1 ad 3.) While what the will is and the end for which it acts are unalterable, its actions still proceed from the will itself. These acts are then called voluntary. On the other hand, the necessities are not, for they are not acts of the will, but principles of its operation.


To what, then, does freedom apply? Obviously not in coercion, for that does not even pertain to the will. Freedom does not apply to the necessities of nature or the general end, for these are not the objects of the will (except perhaps the latter in the next life) but the principles of willing. Freedom does apply to the exercise or non-exercise of the will and to the acts of the will with regard to particular ends as means to the general end. Citing Aristotle in chapter 48 of the second book of the Summa Contra Gentiles, St. Thomas says that the will is the principle of the self motion in humans. That is, humans are free to exercise their will and to choose particular things.(DV 24.1.)

The will of necessity wills universal goodness as it end and elicits its act by means of reason. It cannot do otherwise while still being a rational appetite. Since this tendency is according to the will, it is voluntary. Any choice of the will for universal goodness, because it is in accord with the principles of volition, is voluntary. Aquinas does not consider this general tendency toward the good as free since it is determined necessarily.(ST Ia, 83, 1 ad 5.)

The will however is an intellectual power, its activity presupposes knowledge. In considering the voluntary movement toward universal goodness as being necessary and not free, Aquinas is considering a very special case: knowledge of universal goodness. For Aquinas, the Good itself is God, and knowledge of the Good is attainable only in the beatific vision after death. In this situation, we will will voluntarily the Good, but not do it freely.

This point on knowledge is the fundamental foundation for the wills freedom. In the present life, no one object can be considered by our reason as totally good and so does not move the will necessarily to will it in particular. The will must necessarily be moved by the good or apprehended good thing, no one thing so exhausts goodness that the will is moved to it necessarily.( ST Ia, 105, 4) Many things possess goodness to varying degrees and with various aspects, such that several particular goods may be contrary or, in their various aspects, even contradictory. Therefore no one thing is sufficient to move the will necessarily. Not even the consideration of the goodness of things is completely good, so that people are free to judge or not judge particular objects. Hence, the will is free both in its exercise and in its specification, ie. choosing one good over the other.

On the other side, in the way the will acts, freedom is also preserved, since every act of the will is particular. The specific act of the will cannot encompass the entirety of universal goodness be cause of its specificity. So even choosing to act over not acting does not fulfill the will's necessity toward goodness.( ST Ia-IIae, 13, 6) Also, because no particular means is necessary for the attainment of goodness or happiness, there is freedom. The will might not choose any particular means to its end because it is not bound by the necessity of utility.(DV 24.2.) The will is free to specify its acts after it chooses to act at all.

In St. Thomas's analysis of the human will and its freedom, he first starts with the assumption that it is. He also analyses freedom assuming that the will naturally tends toward goodness, being itself an appetitive power. These two assumptions, while indicated by common experience, are hardly the ground to argue against a modern notion that considers freedom the will's end or natural inclination. Freedom for St. Thomas is the manner in which intellectual beings seek universal goodness. It is a condition of the will arising from our nature being in the kind of world that we inhabit.

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