Lesson 2: Speculative and Practical

When St. Thomas commented on Boethius's On the Trinity, chapter two of that little work provided him with an occasion to speak of the division of speculative philosophy into a number of different sciences. But before getting into that, he has this to say:

It should be said that theoretical or speculative intellect properly differs from the operative or practical in this, that the speculative has for its end the truth it considers, whereas the practical has for its end the putting into practice of a known truth. (In Boethii de trin., q. 5, a.1)

And he goes on to say that this is why Aristotle in On the Soul says that they differ from one another in their end. The reference is the chapter ten of Book Three of that Aristotelian work, and it can be taken as a classical expression of the doctrine. It is difficult to find a place where Thomas mentions the distinction between speculative and practical intellect that he does not refer us to this locus classicus in Aristotle.

Suggestion: You can compile a list of places where Thomas speaks of the speculative and practical by consulting the Index Thomisiticus, the CD ROM data base containing all of Thomas's writings with an access program that enables us to compile such lists. The Past Master CD ROM database does the same for the works of Thomas in English translation. The old-fashioned way is far from being surpassed, of course, and you will be greatly aided by Peter of Bergamo Tabula Aurea.

Let us have before us the locus classicus:

10 These two at all events appear to be sources of movement: appetite and mind (if one may venture to regard imagination as a kind of thinking; for many men follow their imaginations contrary to knowledge, and in all animals other than man there is no thinking of calculation but only imagination.

Both of these then are capable of originating local movement, mind and appetite: (1) mind, that is, which calculates means to an end, i.e. mind practical (it differs from mind speculative in the character of its end); while (2) appetite is the stimulant of mind practical; and that which is last in the process of thinking is the beginning of the action. It follows that there is a justification for regarding these two as sources of movement, i.e. appetite and practical thought; for the object of appetite starts a movement and as a result of that thought gives rise to movement, the object of appetite being to it a source of stimulation. So too when imagination originates movement, it necessarily involves appetite.

[The text of Aristotle is conventionally referred to in this way: On the Soul, III, 10, 433a9-21. That is, Book Three, chapter ten, page 433, column a, lines 9 through 21. The page referred to is that of the 19th century Berlin Academy edition of the Greek text, whose editor was Bekker. Accordingly, such page references are called the Bekker numbers. By referring to the text in this way, a uniformity is retained across the many languages into which the work has been translated (later editions of the Greek text also retain Bekker's numbers), which is a great convenience for scholars.]

Text and Context

It is risky to assume that we can lift a passage like this from a book and easily grasp what it has to say. If it is the tenth chapter in the third book, an understanding of the preceding chapters is presumably presupposed. And an understanding of Book Three, doubtless requires understanding of Books One and Two. But there is more.

Aristotle's work On the Soul, is part of a vast project of his to understand the natural world. Not only that, but he had very definite ideas as to how we should go about this study. The study of nature begins with the Physics in which Aristotle studied natural things, physical objects -- that is, things that come to be as the result of a change -- in their common principles. That is, before getting into the difference between living and non-living natural things.

Perhaps you have heard that Aristotle taught something called the hylomorphic theory of physical objects. This does scant justice to what he says -- it is certainly not a theory in our sense of the term.

Aristotle is concerned with the macroscopic objects around us and our daily commerce with them. Of them all, he suggests, we would agree that they come into being, undergo ceaseless change and eventually pass out of being. Calling them physical -- ta physika -- captures that. What are the first and most obvious things that we can say of such things? We do not, Aristotle points out, first gain distinct and specific knowledge of one thing and then move on to another. Rather, we initially gather things into great predicable wholes, or genera -- for example, physical objects, all the things that come to be as the result of a change. Some things can be truly said of all of them prior to going into their differences from one another.

Aristotle takes as example the commonplace occurrence of someone's learning a skill, say, how to play the harp. This change can be expressed in three different ways.

  1. Man becomes musical.
  2. The non-musical becomes musical.
  3. The non-musical man becomes musical.

Nothing at all profound is intended by this. It is simply the case that these are three different ways of expressing the same change. Of course Aristotle has a point in pointing this out.

All of these expressions involve the form: A becomes B. Sometimes, however, we speak of change in this way: From A, B comes to be. Can we re-express 1, 2 and 3 above in this second form? Of course we can. But Aristotle thinks we would be reluctant to express 1 as From man, musical comes to be, though we would have no such reluctance in putting 2 and 3 this way. Why?

The grammatical subject of 1 is also the subject of the change.

The grammatical subjects of 2 and 3 are not the subjects of the change expressed. The reason for this is what is meant by "subject of a change."

The subject of a change = df. that to which the change is attributed and which survives the change. Obviously only the person who learns how to play the harp survives; his inability to play the harp does not survive his learning how to play the harp, nor does the compound, "the non-musical man," i.e. the non-harp playing person.

Such considerations lead to the following observation. Every change involves minimally a subject, a privation in the subject, and a form which is the opposite of the privation. Man, non-musical, musical.

Subject, privation, property.

But the terminology Aristotle hits upon derives from another example he uses, that is, of unshaped wood being shaped into a likeness of someone. The Greek term for wood is hyle; morphe is Greek for shape. These become matter and form. That is why, the elements of any change are said to be matter, form and privation. And also why Aristotle is said to teach hylomorphism.

It is not only such existing units as persons and pieces of wood that are subject to change. These autonomous and self-standing things also come into being and pass out of being. While such a thing -- Aristotle calls it a substance -- exists its changes are incidental. That is, when Percy learns how to play the harp, the harp-playing Percy comes into being, but not Percy just as such. As the subject of such an incidental change, the subject or substance precedes it and survives it. But what about the coming into being of substance as such?

The things a substance has, acquires and loses, are called its accidents. They befall it, and they make it be this or that, but not to be absolutely speaking. We might think that when Percy comes into being, something that was not Percy has become Percy. But this would make being-Percy an accident of some substance, so Percy would not be an ultimate unit. Against this is the fact that, if you were asked to count up the basic things in the room, Percy would be among them -- if he is in the room. Human persons are basic units if anything is. And basic countable unit is a sort of synonym for substance. If there are substances and if substances come to be, and if the above analysis is valid, the result of such substantial becoming is a composite of matter and form. The matter here, what comes to have the form thanks to which a man is a man, cannot itself be a substance, since then this would not be an instance of substantial change, but only another example of accidental change. To make this point Aristotle called the subject of substantial change prime matter.

The form prime matter acquires in a substantial change -- the result of which is a new autonomous unit -- is called its substantial form. To be human is a far more fundamental thing to say of Percy than to be seated, to be hungry, to be tan, etc.

The substantial form of living things is called its soul. Among other things, this means that to be alive is of the essence of a living thing; it is not some attribute a non-living substance might acquire and lose. If the soul is the first principle of life in living things, and living things are distinguished from non-living things because they exhibit such activities as growing, taking nourishment, moving themselves, awareness, wanting, etc., it becomes necessary to distinguish the soul from its capacities, faculties or powers (those are synonyms). To see is to actuate a possibility; to hear is to actuate a possibility. The soul itself cannot be the potency that is actuated because if it were, seeing and hearing would be identical, that is, the same actuation.

One could go on, and in another course, one would. Meanwhile: 

Reading Assignment

Penguin Thomas Aquinas Selected Writings, selection 17.

Writing Assignment

One page stating as clearly and succinctly as you can the difference between the theoretical and the practical.


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