The Science of Being as Being

Aristotle's Theory of Existence

The Metaphysics, as it exists now, is divided into fourteen books named according to the letters of the Greek alphabet.

Book I: Alpha (Α)
Book II: little Alpha (α)
Book III: Beta (Β)
Book IV: Gamma (Γ)
Book V: Delta (Δ)
Book VI: Epsilon (Ε)
Book VII: Zeta (Ζ)
Book VIII: Eta (Η)
Book IX: Theta (Θ)
Book X: Iota (Ι)
Book XI: Kappa (Κ)
Book XII: Lambda (Λ)
Book XIII: Mu (Μ)
Book XIV: Nu (Ν).

The title (τὰ μετὰ τὰ φυσικά, "the books after the physical treatises") was imposed by later editors. It refers to the position of the Metaphysics within the Aristotelian corpus. It is after the physical works and before the ethical works.

The Metaphysics reads not like a finished product but more like a series of notes written at different times.

Books II, V, and XI seem to be later additions.

Books VII and VII appear to be the beginning of a new work, not a continuation of the books from Book I.

Book XII appears to be an independent work.
Aristotle describes his inquiry in the Metaphysics as "theology" and "first philosophy."

This raises the question of what unifies theology and first philosophy so that they are one subject. First philosophy is the study of "being as being." Theology is a study of divine objects. Theology and first philosophy thus appear to be different subjects. Theology is a study of some of the beings there are, the divine objects. First philosophy is a study of being in general.

Theology is First Philosophy


"Long ago, now, and always, what is sought after and always puzzled over, what is being (ὄν), is the question what is substance (οὐσία). Some say that it is one; others, more than one; some, finite others, infinite. And so for us too our chief and primary and practically our only concern is to investigate what this way of being is" (Metaphysics VII.1.1028b).

The noun οὐσία comes from a participle of the verb εἰμί (whose first-person meaning is "I am, I exist"). The infinitive is εἶναι ("to be"). The present participles are ὤν (masculine), οὖσα (feminine), ὄν (neuter).

οὐσία is translated as substantia (which is the literal translation of ὑπόστασις (ἵστημι ("stand") + ὑπό ("under")) because other things depend on the substances for their existence.
Theology, however, is first philosophy, according to Aristotle, because the way of being or existing that characterizes divine objects is the most general way of being.

What Aristotle has in mind is not easy to grasp, but it is possible to make some progress.

Different things have different ways of being or existing A human has the way of being of a "substance" (οὐσία). Humans are substances. Good, bad, pale, and hot have a different way of being. They have the way of being of a quality. The are not substances. They are qualities. Three-cubits has the way of being of a quantity. Three-cubits is a quantity. Further, Aristotle thinks that all other things (qualities, quantities, and so on) exist because substances exist.

"Being is said in many ways.... It signifies, on the one hand, the what it is and some this (τί ἐστι καὶ τόδε τι), and on the other hand, the quality or quantity or any other such category. Being is said in these ways, but it is evident that primary among them is the what it is, for this signifies the substance (for when we say what quality something is, we say that it is good or bad, not three-cubits or man, but when we say what it is, we say man or god, not pale or hot or three-cubits), and the other things are all said to be because some are quantities of what is, others are qualities, others again affections, still others something else" (Metaphysics VII.1.1028a).

Substances also have ways of being or existing. One way is as a form in matter, but this is not the primary way of being a substance. Divine objects are substances in the primary way. They are forms, and the being of other substances are qualifications of this primary way of being.

Theology, then, as the study of divine beings, is a study of objects whose being is the primary way of being. This makes theology first philosophy. Physics is second philosophy because it is a study of objects whose ways of being is a qualification of the being of divine objects. Natural bodies are forms, but they are forms with qualification. They are forms in matter.

"The theoretical sciences are to be preferred to the other sciences, and theology to the other theoretical sciences, but one might wonder whether first philosophy is universal or deals with some genus and one kind. .... If there is no other substance (οὐσία) besides those which are naturally composed, physics will be the primary science; but if there is a substance which is immutable (ἀκίνητος), "First philosophy treats of things which are both separable and immutable (ἡ δὲ πρώτη καὶ περὶ χωριστὰ καὶ ἀκίνητα)" (Metaphysics VI.1.1026a).

Aristotle sometimes marks no distinction between κίνησις ("motion") and μεταβολή ("change").

"There is no such thing as motion (κίνησις) over and above the things. For, wherever anything changes, it always changes (μεταβάλλει γὰρ τὸ μεταβάλλον) either from one thing to another, or from one magnitude to another, or from one quality to another, or from one place to another.... So neither motion nor change (οὐδὲ κίνησις οὐδὲ μεταβολὴ) can exist apart from these" (Physics III.1.200b).)

Other times he use κίνησις for change in place, quality, and quantity and uses μεταβολή as the more general term.
the science which studies this will be prior to physics, and will be first philosophy, and universal in this way, that it is primary. It will be for this science to study being as being; what it is, and what the attributes are which belong to it as being" (Metaphysics VI.1.1026a).

It is possible to get some insight into how first philosophy is "universal" thinking about what explanations would be part of physics if the there were no "substance which is immutable." In there were no such substances, there would be two theoretical sciences: physics and mathematics. Because physics would be first philosophy, it would fall to physics to explain the existence of the magnitudes that (Aristotle thinks) constitute the domain of mathematics. Magnitude is an essential feature of the sensible substances physics studies, so the explanation of the existence of sensible substances will include an explanation of the existence of magnitudes.

Since, as Aristotle thinks, there are immutable substances, there must be something about the existence of these divine substances that somehow introduces the features that characterizes the sensible substances. It falls to theology, because as first philosophy it is "universal," to explain these features as part of its explanation of the existence of the divine substances.

The Being of Substance

It is because Aristotle is interested in this "universal" explanation in first philosophy that he turns his attention to the way of being or existing that belongs to substance.

"We must consider what things are substances; and whether there are any besides the sensibles, or not; and how these substances exist; and whether there is any separable substance (χωριστὴ οὐσία), and if so, why and how, or none besides the sensibles" (Metaphysics VII.2.1028b).

This interest in the existence of substance in the Metaphysics constitutes a departure from his practice in the Categories. Whereas in the Categories Aristotle is primarily a critic of Plato's ontology, in the Metaphysics he sees something important in in this ontology.

Aristotle sets out conditions something must meet to be a substance. A substances is a "subject" for the predication of properties, is "separate" from its properties in such a way that its properties depend on it for their existence, and has a oneness and unity and so is a "this."

Further, although he recognizes that there are puzzles that stand in the way of clearly understanding how form meets these conditions, Aristotle seems to think that theology explains the existence of divine substances somehow as forms and that the principles of this existence explain the existence of sensible substances in the domain of physics.

"We have now stated in outline the nature of substance—that it is that which is not of a subject (ὑποκειμένου), but of which the other things are. But we must not merely define it so, for it is not enough Not only is the statement itself obscure, but also it makes matter substance. ... But this is impossible; for it is accepted that separateness (τὸ χωριστὸν) and a this (τὸ τόδε τι) belong especially to substance. Hence it would seem that the form and the combination of form and matter are more truly substance than matter is. The substance, then, which consists of both—I mean of matter and form—may be dismissed, since it is posterior and obvious. Matter too is in a sense evident. We must consider the third type, [the form,] for [whether or not] this [meets the conditions for being a substance] is the most perplexing" (Metaphysics VII.3.1029a).

The details of Aristotle's investigation are difficult to follow, but it is possible to get some insight into his project once it is clear why he abandons the position he set out in the Categories.


Perseus Digital Library:

Aristotle, Metaphysics
Henry George Liddell, Robert Scott, A Greek-English Lexicon:
οὐσία, ousia, noun, "substance"
ποιός, adjective, "of a certain kind or quality"
ποιότης, noun, "quality"
ὑπόστασις, hypostasis, noun, "standing under, supporting"

Charlton T. Lewis, Charles Short, A Latin Dictionary:
immutabilis, adjective, "unchangeable, unalterable, immutable"
qualitas, noun, "quality"
quantitas, noun, "quantity"
substantia, noun, "that of which a thing consists"




"Traditionally οὐσία has been rendered by 'substance.' The reason for this is that, on the view Aristotle puts forward in the Categories, properties depend for their being on objects in that objects are their ultimate subjects, they are what ultimately underlies everything else. Indeed, objects in the Categories are characterized by the very fact that they are the ultimate subjects which underlie everything, whereas there is nothing that underlies them as their subject. It is because of this characterization that the rendering 'substance' seems appropriate" (Michael Frede, "Substance in Aristotle's Metaphysics," 73. Essays in Ancient Philosophy, Michael Frede (University of Minnesota Press, 1987), 72-80).

"Horses are a kind of beings, and camels are a different kind of beings, but neither horses nor camels have a distinctive way of being, peculiar to them; they both have the way of being of natural substances..., as opposed to, e.g., numbers which have the way of magnitudes..." (Michael Frede, "The Unity of General and Special Metaphysics: Aristotle's Conception of Metaphysics," 85-86. Essays in Ancient Philosophy, Michael Frede (University of Minnesota Press, 1987), 81-95).

"[W]e shall want the substance of an object to be such that with reference to it we can explain how, despite all the changes, it is the history of one object. We also think an object might have had a history quite different from the one it actually had yet have been the same object; this, too, is to be explained in terms of substance. Furthermore, the substance must be an individual, since we are looking for the real individuals in the category of substance which are to explain the individuality of ordinary individual objects. Finally, there must be some sort of asymmetry between substances and properties, on the basis of which we can say of properties and everything else that exists that they depend on substances for their existence, but that substances do not, in any way, depend on properties for their existence. These are the requirements Aristotle lays down in the Metaphysics, when he says a substance must be a subject (hypokeimenon [ὑποκείμενον]), "a this" (tode ti [τόδε τι]), and an independently existing entity (choriston [χωριστὸν])" (Michael Frede, "Individuals in Aristotle, 64-65. Essays in Ancient Philosophy, Michael Frede (University of Minnesota Press, 1987), 49-71).

"Aristotle in [Metaphysics] E 1, 1026a23 ff. raises the question of whether first philosophy is universal rather than just concerned with with a particular domain of reality, namely divine substances. And the suggested answer seems to be that first philosophy does not just deal with a particular domain of of objects, but is universal, because it is first. Thus, if there were no separate immaterial substances, physics would be first, but for this very reason physics would not just deal with a particular domain, namely sensible substances, but would be universal in dealing in some way with everything there is. ... If there were no immaterial separate substances, we would have two theoretical sciences or rather bodies of sciences, physics and mathematics, the one concerned with sensible substances, the other with magnitudes. Now physics would be universal in the sense that, though its domain does not include magnitudes, it would nevertheless have to say something about magnitudes. For it is a crucial feature of sensible substances that they are of some magnitude and that they come in kinds and form classes which are of some magnitude. One would have to form a view as to what it is to be a magnitude, as to why there have to be magnitudes for there to be sensible substance, as to what kinds of magnitudes one has to assume" (Michael Frede, "Introduction," 8. Aristotle's Metaphysics Lambda: Symposium Aristotelicum, Michael Frede & David Charles (Oxford University Press, 2000), 1-52).




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