Aquinas on Matter and Form and the Elements

A Translation and Interpretation of the De Principiis Naturae and the De Mixtione Elementorum of St. Thomas Aquinas

Joseph Bobik

• Publisher: University of Notre Dame Press
• Year: 1998
• ISBN:
  9780268076337
• Topic: Filosofía
• Subtopic: Filosofía de la religión

Joseph Bobik offers a translation of Aquinas's De Principiis Naturae (circa 1252) and De Mixtione Elementorum (1273) accompanied by a continuous commentary, followed by two essays: "Elements in the Composition of Physical Substances" and "The Elements in Aquinas and the Elements Today." The Principles of Nature introduces the reader to the basic Aristotelian principles such as matter and form, the four causes so fundamental to Aquinas's philosophy. On Mixture of the Elements examines the question of how the four elements (earth, air, fire, and water) remain within the physical things composed from them.

PART ONE

DE PRINCIPIIS NATURAE

De Principiis Naturae¹

Chapter one
Generation and corruption

In chapter one, Aquinas talks about many things: about what can exist, and what does exist; about what is simply (or period), and what is something or other; about matter and form; about prime matter and subject; about generation and corruption, both substantial and accidental; about form, both substantial and accidental; about privation; about art and nature. His comments seem to be aimed at making clear how to think and talk about change -- in particular about change in the natural world. Think and talk about it this way, he seems to be saying, because this is the way it is.

Being: potential and actual; substantial and accidental

1. Nota quod quoddam potest esse licet non sit, quoddam vero est. Illud quod potest esse, dicitur potentia esse; illud quod iam est, dicitur esse actu. Sed duplex est esse: scilicet esse essentiale sive substantiale rei, ut hominem esse, et hoc est esse simpliciter; est aliud esse accidentale, ut hominem esse album, et hoc est esse aliquid.

Take note that some things can exist, though they do not, whereas others do indeed exist. Those which can exist are said to be potentially. Those which already do exist are said to be actually. And this in two ways. There is first the essential or substantial existence of a thing, as for a man to be; and this is to be simply. There is secondly accidental existence, as for a man to be white; and this is to be something or other.

In 1., he observes that some things can exist, though they do not; and these are said to be potentially. Others things do exist; and these are said to be actually. What is the point of these remarks? one might ask. Aren’t they frustratingly obvious, and singularly uninformative? What intellectual advance, of even a minimally clarifying sort, is made by noting that what can exist is said (dicitur) to be potentially? Or that what does exist is said (dicitur) to be actually? Is “what is potentially” any clearer that “what can exist”? Is “what is actually” any clearer that “what does exist”? And does “dicitur” mean: is said in the ordinary, everyday language into which one is born? Or does it mean: is said in philosophical language, for philosophical purposes? And what difference, if any, would that make?

The point of these remarks seems to be to set the stage for a philosophical account of the observed fact of change in the physical or natural world. One way, perhaps the clearest and easiest way, to begin to think about physical or natural change is to think in terms of what can be and what is. For, a thing which is undergoing change both is and can be. It is or exists (and of course, since it is, it also is what it is); and simultaneously can be, though it yet is not, that which it is becoming. It could not be undergoing change if it did not exist (and exist as what it is); nor if it were not true to say of if that it can be (but is not) what it is becoming. To be (to be actually -- what it is), to be able to be (to be potentially -- what it is becoming), and not to be (not to be actually -- what it is becoming) -- these three provide a clear and easy way of beginning to think and to talk about matter (can be), form (is), and privation (is not). These three, i.e., matter, form, and privation -- as Aquinas sees it, and as truth has it -- are the three principles of nature, the three beginning points (principia), or sources, of the process of generation by which natural things are brought into existence.

Aquinas observes further, in 1., that the existence of a natural thing is of two sorts. There is, first, its essential or substantial existence; and this is only one. There is, secondly, its accidental existence; and this is more than one. For example, I exist -- as what I am, i.e., a rational animal. This is my one essential or substantial existence. This is what I am (essential) as an ultimate existing subject (substantial). But, I am also five feet eight inches tall; white, knowledgeable, and virtuous; a father and a son, and taller than my daughter; I am being carried to my son’s house; before that I was at home, sitting on the sofa, at noon, and wearing comfortable slacks. These are among my many accidental existences. None of these is included in what I am essentially, i.e., in my one existence as an ultimate existing subject. They are, one and all of them, added to, over and above, it. The ultimate existing subject is I -- this rational animal. My being five feet eight inches tall, and white, and knowledgeable, etc. -- no one of these is what I am as an ultimate existing subject. Neither is the collection of them what I am as an ultimate existing subject. Furthermore, no one of them, nor the collection of them, is itself an ultimate existing subject.

Matter: prime matter and subject

2. Ad utrumque esse est aliquid in potentia. Aliquid enim est in potentia ut sit homo, ut sperma et sanguis menstruus; aliquid est in potentia ut sit album, ut homo. Et tam illud quod est in potentia ad esse substantiale, quam illud quod est in potentia ad esse accidentale, potest dici materia; sicut sperma hominis et homo albedinis. Sed in hoc differunt, quia materia quae est in potentia ad esse substantiale, dicitur materia ex qua; quae autem est in potentia ad esse accidentale, dicitur materia in qua. Item, proprie loquendo, quod est in potentia ad esse substantiale, dicitur materia prima; quod vero est in potentia ad esse accidentale, dicitur subiectum. Unde dicitur quod accidentia sunt in subiecto; non autem dicitur quod forma substantialis sit in subiecto. Et secundum hoc differt materia a subiecto, quia subiectum est quod non habet esse ex eo quod advenit, sed per se habet esse completum; sicut homo non habet esse ab albedine. Sed materia habet esse ex eo quod sibi advenit, quia de se habet esse incompletum. Unde, simpliciter loquendo, forma dat esse materiae, accidens autem non dat esse subiecto, sed subiectum accidenti, licet aliquando unum ponatur pro alio, scilicet materia pro subiecto, et e converso.

There is something in potency to each of these ways of being. For example, there is something in potency to being a man, like sperm and menstrual blood; and there is something in potency to being white, like man. Both what is in potency to substantial existence, and what is in potency to accidental existence, can be called matter; like sperm, the matter of man; and man, the matter of whiteness. But they differ in this: the matter which is in potency to substantial existence is called the matter out of which; and that which is in potency to accidental existence is called the matter in which. Properly speaking, however, what is in potency to substantial existence is called prime matter; whereas what is in potency to accidental existence is called a subject. Whence it is said that accidents are in a subject; but it is not said that a substantial form is in a subject. And, it is according to this that matter differs from a subject: a subject does not have existence from that which comes to it; rather it has existence, complete existence, of itself; man, for example, does not have existence from whiteness. Matter, on the other hand, does have existence from that which comes to it, for of itself it has an incomplete existence. Whence, simply speaking, form gives existence to matter; whereas an accident does not give existence to a subject, but the subject to the accident; although at times one is used for the other, that is, matter for subject, and conversely.

In 2., Aquinas pursues the opening sentence of 1. “Take note,” he had said as he opened 1, “that some things can exist, though they do not, whereas others do indeed exist.” He points out here, as he begins 2., that just as there are two sorts of actual existence, there are correspondingly two sorts of potential existence. “There is something in potency to each of these ways of being,” i.e., 1) to essential or substantial existence, or to being simply, like sperm and menstrual blood (it is really the ovum, as we know today, not the menstrual blood) to being a man; and 2) to accidental existence, or to being additionally something or other, like man to being white. And both of these can be called matter. Sperm can be called the matter of man, and man the matter of whiteness. But each is a different sort of matter. This is why the matter which is in potency to substantial existence is called the matter out of which, to indicate that this matter is an ingredient of the ultimate existing subject; and why the matter which is in potency to accidental existence is called the matter in which, to indicate that this matter is not an ingredient of the ultimate existing subject, but rather the ultimate existing subject itself. The difference between the two matters can be made clearer by calling the first prime matter, to indicate that there is nothing prior to it (since it is prime, i.e., first) which is related to it as its matter, that of itself it has no substantial form, and that therefore it does not exist of itself; and by calling the second a subject, to indicate that there is something prior to it, namely prime matter, which is related to it as its matter, that it has a substantial form, and that it does indeed exist of itself. This is why it is said that accidents, i.e., accidental forms, are in a subject (an ultimate existing subject); and why it is not said that substantial forms are in a subject. Rather, substantial forms are in prime matter, which does not exist of itself, not being an ultimate existing subject, though it is an ultimate subject. Prime matter, having an incomplete existence, has existence from that which comes to it, i.e., from the substantial form. But the subject, having a complete existence, does not have existence from the accidental forms which come to it. Rather the accidental forms have existence from the subject. Though “matter” is most properly used to designate what is in potency to substantial existence, and “subject” to desginate what is in potency to accidental existence, sometimes one is used for the other, i.e., “matter” for “subject,” and vice versa.

Aquinas had said above both 1) that sperm and ovum are in potency to being a man, i.e., in potency to substantial existence; and 2) that the matter which is in potency to substantial existence is prime matter. Is one to conclude, therefore, that sperm and ovum are the same as prime matter? -- It seems that not; for prime matter of itself is absolutely formless, has no form of any sort; whereas sperm and ovum, both, do indeed have a form. Besides, though prime matter is in potency to all substantial forms, it is in potency to them in a certain order. Prime matter is in potency, first of all, to the lowest of the substantial forms, i.e., to the substantial forms of the elements, and through these to the substantial forms of mixed bodies, some of which become the food which is appropriate for human consumption. Human bodies produce sperm and ova out of some of this food, and the sperm and ova, in turn, via fertilization and gestation, become new human beings. In some way, the elements remain in mixed bodies, including human bodies. How they remain will be considered later on, at a more opportune point.

Form: substantial and accidental

3. Sicut autem omne quod est in potentia potest dici materia, ita omne a quo aliquid habet esse, sive substantiale sive accidentale, potest dici forma; sicut homo, cum sit potentia albus, fit actu albus per albedinem, et sperma, cum sit potentia homo, fit actu homo per animam. Et quia forma facit esse in actu, ideo forma dicitur esse actus. Quod autem facit actu esse substantiale, dicitur forma substantialis, et quod facit actu esse accidentale, dicitur forma accidentalis.

Now just as everything which is in potency can be called matter, so too everything from which something has existence, whether substantial or accidental, can be called form. For example, man, being potentially white, becomes actually white because of whiteness; and sperm, being potentially man, becomes actually man because of the soul. Now, because form causes actual existence, form is said to be an act. What causes actual substantial existence is called a substantial form; and what causes actual accidental existence is called an accidental form.

Having talked about matter, i.e., about what is in potency, in 2., Aquinas turns in 3. to talk about form. Form is the actuality of the potentiality which is matter. Whereas matter is that in a changing thing by which that thing can be what it is becoming; form is that, in a thing which has come to be, by which that thing is actually, now, what it was, before, only potentially (in its matter). The soul is that, in a human being which has come to be, by which the human being is a human being, i.e., by which the human being differs from the sperm and ovum out of which it came to be. To be sure, something of the sperm and ovum (i.e., prime matter, and certain elements, and certain accidental forms) survives and remains in some way in the human being which has come to be. And certain of these remaining ingredients, namely prime matter and the elements, together with the soul, constitute the essence of the human being which has come to be, and this essence differentiates that human being from nothingness. Not only does the human being differ from the sperm and ovum, the matter out of which it came to be, by reason of the human soul (this is the substantial form, the forma partis); but it differs from nothingness as well, by reason of its essence, i.e., by reason of the composition of what survives in it (from that out of which it came to be) and the human soul (this composite is the essence, the forma totius). Form differentiates. The substantial form, the forma partis, differentiates from matter. The essence, the forma totius, differentiates from nothingness.

Generation: substantial and accidental

4. Et quia generatio est motus ad formam, duplici formae respondet duplex generatio: formae substantiali respondet generatio simpliciter; formae accidentali generatio secundum quid. Quando enim introducitur forma substantialis, dicitur aliquid fieri simpliciter, sicut dicimus: homo fit vel homo generatur. Quando autem introducitur forma accidentalis, non dicitur aliquid fieri simpliciter, sed fieri hoc; sicut quando homo fit albus, non dicimus simpliciter hominem fieri vel generari, sed fieri vel generari album.

Because generation is a motion to form, there are two kinds of generation corresponding to the two kinds of form. There is generation simply, which corresponds to substantial form. And there is generation with respect to something or other, and this corresponds to accidental form. When a substantial form is introduced, something is said to come to be simply. We say, for example, that a man comes to be, or that a man is generated. But when an acccidental form is introduced, it is not said that something comes to be simply, but that it comes to be this. When a man comes to be white, for example, we do not say simply that the man comes to be, or that he is generated; but that he comes to be, or is generated as, white.

In 3., Aquinas had talked briefly about form, and about its two types, substantial and accidental. In 4., he turns to talk about generation, the way to form. And he begins by pointing out that generation is a certain sort of motion, or movement, which terminates in form. This implies, of course, that generation begins with, departs from, matter and privation. Generation is the passage, the change, from matter and privation to form. There are two kinds of generation, one with respect to each kind of form. There is 1) generation simply, the way to substantial form; in which case a thing comes to be as an ultimate existing subject, e.g., as a human being. There is 2) generation as something or other, the way to a...