Lesson 3: Degrees of Practical Knowledge

Thomas, like Aristotle, speaks of practical intellect and speculative or theoretical intellect, but he does not mean to suggest that these are two different capacities or powers of the soul. They are two different kinds of mental activity in which we can engage because we have a mind. It is because they have different aims or ends that we distinguish them.

The end of theoretical thinking is the perfection of the thinking process itself, namely, truth. Once we know what a thing is, how it is with that thing, the properties and activities of that thing, and the like, our intellectual quest is satisfied. What is it? Say, we discover the thing's definition. That ends that quest. But then we ask something else. What does it do that nothing else does? The answer to that satisfied that quest. In such cases, getting straight about the way things are, that is, acquiring the truth about them, is what we want. The end of theoretical thinking is truth.

Sometimes we use our minds in such a way that just knowing the way things are is not the end of the inquiry. Rather, we want that kind of knowledge in order to do something or in order to make something. Truth here looks to be a means to the perfection of activities other than thinking. I need a lot of truths, that is, I have to know lots of things -- about wood and plastic and displacement and shapes that cleave the water, etc. -- in order to build a boat, but I want to know such things in order to build a boat.

Their different ends are the basic way that theoretical and practical thinking are distinguished. Aristotle provided the text [On the Soul, III, 10] to which Thomas refers whenever this matter comes up. But there is another text in which he suggests a number of other criteria for distinguishing the theoretical from the practical, thus enabling us to speak of degrees of practical knowing. Thus, we needn't say simply that an instance of knowing just is or is not practical and that's the end of it; we can say that in one or more respects it is practical whereas in others it is theoretical.

The passage from St. Thomas that we examined in the previous lesson contrasts the practical and theoretical uses of our mind. The chief difference lies in the end or purpose of the two: when the end or thinking is simply to arrive at the truth of some matter, it is the perfection of thinking as such that is sought. But sometimes we seek the truth, not as a terminal goal, but with the eye to some activity other than thinking. This is what we mean by practical thought. Learning how to make a boat in your basement is knowledge whose fulfillment is had when you make a boat in your basement. Merely to annotate the article in Boating, to grasp how each step is to be taken, and do nothing about it, seems rather pointless. And it is, since the point of such knowledge is not just knowing, but doing. The knowledge is sought to govern or influence some activity other than thinking.

We are going to look at a passage from the Summa theologiae in which Thomas is asking whether God has theoretical or practical knowledge of things. That we should appeal to such a discussion for our present purposes may surprise, but it is not unusual for Thomas to flesh out and develop philosophical points prior to putting them to a theological purpose. This what goes on in the following text:

Summa theologiae, Ia, q. 14, a. 16

Utrum Deus de rebus habeat scientiam speculativam.

Ad decimumsextum sic proceditur. Videtur quod Deus de rebus non habeat scientiam speculativam.

1. Scientia enim Dei est causa rerum, ut supra ostensum est. Sed scientia speculativa non est causa rerum scitarum. Ergo scientia Dei non est speculativa.

2. Praeterea, scientia speculativa est per abstractionem a rebus: quod divinae scientiae non competit. Ergo scientia Dei non est speculativa.

Whether God has speculative knowledge of things.

Turning now to the sixteenth article: it seems that God does not have speculative knowledge of things.

1. For God's knowledge is the cause of things, as has been shown. But speculative knowledge is not the cause of what is known. Therefore God's knowledge is not speculative.

2. Moreover, speculative knowledge arises from abstraction from things, which is not the case with divine knowledge. Therefore God's knowledge is not speculative.

Sed contra, omne quod est nobilius, Deo est attribuendum. Sed scientia speculativa est nobilior quam practica, ut patet per Philosophum in principioMetaphysicorum. Ergo Deus habet de rebus scientiam speculativiam.

Respondeo dicendum quod aliqua scientia est speculativa tantum, aliqua practica tantum, aliqua vero secundum aliquid speculativa et secundum aliquid practica. Ad cuius evidentiam, sciendum est quod aliqua scientia potest dici speculativa triplicter. Primo, ex parte rerum scitarum, quae non sunt operabiles a sciente; sicut est scientia hominis de rebus naturalibus vel divinis.Secundo, quantum ad modum sciendi: ut puta si aedificator consideret domum definiendo et dividendo et considerando universalia praedicata ipsius. Hoc siquidem est operabilia modo speculativo considerare, et non secundum quod operabilia sunt: operabile enim est aliquid per applicationem formae ad materiam, non per resolutionem compositi in principia universalia formalia.Tertio, quantum ad finem: nam 'intellectus practicus differt fine a speculativo,' ut dicitur in III de anima. Intellectus enim practicus ordinatur ad finem operationis: finis autem intellectus speculativi est consideratio veritatis. Unde si quis aedificator consideret qualiter posset fieri aliqua domus, non ordinans ad finem operationis, sed ad cognoscendum tantum, erit quantum ad finem speculativa consideratio, tamen de re operabili. -- Scientia igitur quae est speculativa ratione ipsius rei scitae, est speculativa tantum. Quae vero speculativa est vel secundum modum vel secundum finem, est secundum quod speculativa et secundum quid practica. Cum vero ordinatur ad finem operationis, est simpliciter practica.

ON THE CONTRARY. The more noble is always to be attributed to God. But speculative knowledge is more noble than practical, as is clear from the Philosopher at the beginning of the Metaphysics. Therefore God has speculative knowledge of things.

RESPONSE. It should be said some knowledge is speculative alone, some practical alone, and some in one respect speculative and in another respect practical. To see this consider that a science can be called speculative in three ways. First, with respect to the things known, which are not doable by the knower, e.g. man's knowledge of natural and divine things. Second, with respect to the manner of knowing: for example, if a builder were to consider a house by way of defining and dividing and considering its universal predicates. This is to consider operable things in a speculative manner and not insofar as they are operable: a thing is operable by the application of form to matter, not by analyzing the composite into universal formal principles. Third, with respect to the end, for 'practical intellect differs from speculative in its end,' as is said in 3 de anima. Practical intellect is ordered to activity as its end, whereas the end of the speculative intellect is the consideration of truth. Hence if a builder should consider how a certain house might come to be, without ordering it to the end of operation, but to knowing alone, this would be, with respect to its end, a speculative consideration, though of an operable object. -- Therefore knowledge which is speculative by reason of the thing known is speculative alone, but what is speculative with respect to either mode or end is speculative in one sense and practical in another. But when it is ordered to the end of operation it is simply practical.

Secundum hoc ergo, dicendum est quod Deus de seipso habet scientiam speculativam tantum: ipse enim operabilis non est. De omnibus vero aliis habet scientiam et speculativam et practicam. Speculativam quidem, quantum ad modum: quidquid enim in rebus nos speculative cognoscimus definiendo et dividendo, hoc totum Deus multo perfectius novit. Sed de his quae potest quidem facere, sed secundum nullum tempus facit, non habet practicam scientiam, secundum quod practica scientia dicitur a fine. Sic autem habet practicam scientiam de his quae secundum aliquod tempus facit. Mala vero, licet ab eo non sint operabilia, tamen sub cognitione practica ipsius cadunt, sicut et bona, inquantum permittit vel impedit vel ordinat ea: sicut et aegritudines cadunt sub practica scientia medici, inquantum per artem suam curat eas.

Ad primum ergo dicendum quod scientia Dei est causa, non quidem sui ipsius, sed aliorum: quorundum quidem actu, scilicet eorum quae secundum aliquod tempus fiunt; quorundum vero virtute, scilicet eorum quae potest facere, et tamquam nunquam fiunt.

Ad secundum dicendum quod scientiam esse acceptam a rebus scitis, non per se convenit scientiae speculativae, sed per accidens, inquantum est humana.

Ad id vero quod in contrarium obicitur, dicendum quod de operabilibus perfecta scientia non

On this basis it should be said that God has of himself knowledge that is speculative alone; of other things he has speculative and practical knowledge. Speculative in manner, for whatever things we know speculatively by defining and dividing, God knows much more perfectly. But of the things which he could indeed make but at no time makes he does not have practical knowledge insofar as this is read from the end. Thus he has practical knowledge of things he at some time makes. Evils, though they are not doable by him yet fall under his practical knowledge, along with goods, insofar as he permits or impedes or orders them: thus do sicknesses fall to the practical knowledge of the physician, insofar as he can through his art cure them.

Ad 1. It should be said that God's knowledge is cause, not of himself, but of other things; of some actually, namely those which at some time come to be, of others virtually, namely those he can make yet never makes.

Ad 2. It should be said that it is not an essential note of speculative knowledge that it be taken from the things known, but only accidentally, insofar as it is human.

As for what was said ON THE CONTRARY, it should be said that

non habetur, nisi sciantur inquantum operabilia sunt. Et ideo, cum scientia Dei sit omnibus modis perfecta, oportet quod sciat ea quae sunt a se operabilia, inquantum huiusmodi, et non solum secundum quod sunt speculabilia. Sed tamen non receditur a nobilitate speculativae scientiae: quia omnia alia a se videt in seipso, seipsum autem speculative cognoscit; et sic in speculativa sui ipsius scientia, habet cognitionem et speculativam et practicam omnium aliorum.

Perfect knowledge of operable things is had only insofar as they are operable. Therefore, since God's knowledge is in every way perfect, he must know things doable by him and not only insofar as they are speculables. Nor does this fall short of the nobility of speculative knowledge, because he sees all other things in himself and he knows himself speculatively and thus in the speculative knowledge he has of himself he has both speculative and practical knowledge of all other things.

In applying this division to moral thought, we would doubtless say that moral philosophy is practical in the sense that it deals with things to be done. It it also sometimes practical in that it treats such things in a practical way, giving us precepts and advice on how to behave. But practical knowledge in the fullest sense is only exemplified in singular acts.

If this is how practical knowledge is sorted out in the case of moral philosophy, it will lead to different expectations at different levels of moral knowledge. Clearly, general or abstract knowledge of what we ought to do does not, as such, produce good action. One of the oldest questions of moral philosophy has to do with this relationship between knowing what we ought to do and doing it. Plato thought that, if we really knew what we ought to do, then we would do it. So, if we are not doing what we ought to do, it looks as if we don't know what we ought to do. The remedy, then, would seem to be more knowledge. Maybe a course like this.

That is implausible, needless to say. But let this suffice for now. These are issues to which we shall return in what follows.

Reading Assignment

Thomas Aquinas Selected Writings, selection 26. 

Writing Assignment

Write an essay on the theme: Moral Philosophy is Practical Knowledge in several senses.


Purchase This Course                               << Previous               Next >>                                   Return to Top