Skip to main content

What it Means to Be a Human Person – Part 13 - The Thomistic Definition of Matter

            Interestingly enough, the Thomist agrees, in principle, with at least one claim of the Naturalist. In this sense, Thomism is a Christian Naturalism. The Thomist would agree that matter is a basic, substantial, principle of all sensible, material, entities. We saw in a previous post that, for the hylomorphist, matter is one of two principles out of which all material, sensible, things are composed. Though the Naturalist attempts to claim that matter is atoms, or, whatever the natural sciences claim is most basic, the Thomist recognizes that these descriptions do not define what matter is. Rather, an atom, or, whatever seems to be most basic according to the natural sciences at any given time, is simply another form of matter; and this way of explaining it leads us into the Thomistic explanation of matter.

            In his short treatise De Principiis Naturae Aquinas explains what he considers to be the basic principles from which all material things spring. He begins by pointing out what seems to be a platitude, “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.”[1] Aquinas then goes on to explain that, of those things which actually exist, some exist substantially, and others exist only accidentally. Accidental existence is found in a subject, whereas substantial existence describes the thing itself, its essence.

            Earlier we noted that one of the problems with Naturalism is that in attempting to define matter it gives us a list of characteristics, in other words, accidents. Bobik, in his commentary on Aquinas’ De Principiis Naturae, notes that “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.”[2]

            If we apply what we have just seen to the claims of Naturalism, we find that the Naturalist is attempting to say that some substantial entity is the foundation of reality. But we want to know what matter is. Even the most basic substantial entity, be it the atom, or energy, or anything else, is still composed, as we shall see, of matter and form.

            Aquinas goes on to describe what he has already alluded to when he talked about things that exist, do not exist, and potentially exist. “Both what is in potency to substantial existence, and what is in potency to accidental existence, can be called matter…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.”[3]

            Prime matter is pure potency, having no existence by itself. A subject, however, is not pure potency, but is in potency to certain accidents. For example, a child, which is a subject, is in potency to become an adult. Unfortunately, as we all too frequently find out, a child also has the potency to become an inanimate body. When this happens we are always pained, and rightly outraged, but the potency is there from the moment that the child’s form is in act. In order to fully understand pure potency, it needs to be explained in light of form; due to the fact that pure potency is formless, it is only that which can be.

            “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.”[4] Form is that principle which limits matter – potency. Matter is that principle which, makes the form, this individual; it is the principle of individuation. “First matter, the indeterminate but determinable principle which makes possible the transformation of one substance into another; and first form, the determining principle which accounts for the fact that a given substance is the particular thing that it is and not something else [meaning it’s essence]…If first matter represents what a thing can be, first form represents what a thing is.”[5]

            Matter, then, in the Thomistic perspective, is that principle of potency which individuates form - that is, which makes a human person to be this human person (i. e. - Socrates). But matter cannot exist by itself. Without form there can be nothing. This becomes clear when we try to imagine, or think about, or point to, a particular blob of pure matter. It cannot be done. Matter always exists united with form in some way or another. “First matter is separable from first form in thought, though never in fact. There is no such thing as first matter without first form…First matter has no character in itself. It is absolutely featureless, formless, and indefinite, without quality, without quantity. To acquire definiteness and quality, to be earmarked with quantity, it must have first form. It is potentially everything, though it is actually nothing.”[6] As such, matter is not some single substance; rather the most basic substances are subjects that are composed of matter and form, and are potentially other things.

[1]Joseph Bobik, Aquinas on Matter and Form and the Elements (1998; repr., Notre Dame, IN: University of Notre Dame Press, 2006), 1.

[2]Ibid., 3.

 [3]Ibid., 4.

[4]Ibid., 6.

[5]Robert Edward Brennan, Thomistic Psychology: a Philosophical Analysis of the Nature of Man (1941; repr., New York: The Macmillan Company, 1946), 66-67.

[6]Ibid., 67.

Popular posts from this blog

How Kant’s Synthesis of Empiricism and Rationalism resulted in Agnosticism

Immanuel Kant, presented with the extreme empiricism of Hume and the extreme rationalism of Liebniz, which he discovered through the writings Wolff, sought to take a middle road between these two extreme philosophical positions. I would submit that Kant’s synthesis of these two views leads to an agnosticism about what Kant called “the thing-in-itself”, and ultimately to the philosophical positions known as Atheism, determinism, and nihilism.

Kant’s Sources
First of all, Kant was influenced by Hume’s empiricism and Newton’s physics. He saw that the physical sciences, in contrast to rationalistic metaphysics, were actually making advances. They were making discoveries, and building a system of knowledge that accurately described the world of our sense perceptions. Rationalistic metaphysics, on the other hand, was floundering amidst the combating systems that the philosophers were erecting. It did not provide new knowledge, and only led to unacceptable conclusions, such as the Absolute Mon…

A Short outline of Charles Taylor's: The Malaise of Modernity

            This is simply an outline of Taylor’s basic argument in this short work written by Charles Taylor. The idea of this outline is to help the reader understand the book by providing a simple outline of the basic argument that Taylor is presenting here. The book, which is essentially the manuscript is the fruit of a series of presentations that Taylor made at the Massey Conferences which are hosted by Massey College and Radio-Canada, is divided into 10 chapters. In the first chapter Taylor essentially proposes three causes (recognizing that there may be more) of the Malaise of Modernity: (1) Individualism or the Loss of Sense, (2) The Primacy of Instrumental Reason or the Loss of Ends, and (3) The effect on society and politics in general of the loss of sense to an inauthentic individualism and the domination of instrumental reason, or, the loss of true freedom. Taylor considers the first Malaise in chapters 2 to 8, the second in c…


Leisure: The Basis of Culture & the Philosophical Act. Josef Pieper. Translated by Alexander Dru. 1963. Reprint, Ignatius Press, 2009. 143 pp. $12.99. ISBN 978-1-58617-256-5.
            This book is composed of two articles written by the German philosopher Josef Pieper. Though the two articles are intimately connected, they form two distinct works; as such, this book review will begin by giving a brief introduction to the works in question, followed by and exposition of each of the works individually. The two articles that are included in this book, Leisure: the Basis of Culture and The Philosophical Act, were both published in 1947, and, as such, were written during the cultural crisis in Germany that followed the Second World War. Not only did Pieper have the cultural crisis in mind when he wrote these articles, but he was also writing in light of the works of the most well-known German philosopher of the time – Martin Heidegger. As such, any reader who is familiar with Heidegg…