Metaphysics is one of the principal works of Aristotle and the first major work of the branch of philosophy with the same name. The principal subject is "being qua being", or being understood as being. It examines what can be asserted about anything that exists just because of its existence and not because of any special qualities it has. Also covered are different kinds of causation, form and matter, the existence of mathematical objects, and a prime-mover God.

Book IV Chapter 72015-06-06
But on the other hand there cannot be an intermediate between contradictories, but of one subject we must either affirm or deny any one predicate. This is clear, in the first place, if we define what the true and the false are. To say of what is that it is not, or of what is not that it is, is false
Book IV Chapter 82015-06-05
In view of these distinctions it is obvious that the one-sided theories which some people express about all things cannot be valid-on the one hand the theory that nothing is true (for, say they, there is nothing to prevent every statement from being like the statement the diagonal of a square
Book V Chapter 12015-06-05
BEGINNING means (1) that part of a thing from which one would start first, e. g a line or a road has a beginning in either of the contrary directions. (2) That from which each thing would best be originated, e. g. even in learning we must sometimes begin not from the first point and the
Book V Chapter 22015-06-04
Cause means (1) that from which, as immanent material, a thing comes into being, e. g. the bronze is the cause of the statue and the silver of the saucer, and so are the classes which include these. (2) The form or pattern, i. e. the definition of the essence, and the classes which inclu
Book V Chapter 32015-06-04
Element means (1) the primary component immanent in a thing, and indivisible in kind into other kinds; e. g. the elements of speech are the parts of which speech consists and into which it is ultimately divided, while they are no longer divided into other forms of speech different in ki
Book V Chapter 42015-06-03
Nature means (1) the genesis of growing things-the meaning which would be suggested if one were to pronounce the u in phusis long. (2) That immanent part of a growing thing, from which its growth first proceeds. (3) The source from which the primary movement in each natur
Book V Chapter 52015-06-03
We call necessary (1) (a) that without which, as a condition, a thing cannot live; e. g. breathing and food are necessary for an animal; for it is incapable of existing without these; (b) the conditions without which good cannot be or come to be, or without which we cannot get rid or be
Book V Chapter 62015-06-02
One means (1) that which is one by accident, (2) that which is one by its own nature. (1) Instances of the accidentally one are Coriscus and what is musical, and musical Coriscus (for it is the same thing to say Coriscus and what is musical, an
Book V Chapter 72015-06-02
Things are said to be (1) in an accidental sense, (2) by their own nature. (1) In an accidental sense, e. g. we say the righteous doer is musical, and the man is musical, and the musician is a man, just as we say the musician builds
Book V Chapter 82015-06-01
We call substance (1) the simple bodies, i. e. earth and fire and water and everything of the sort, and in general bodies and the things composed of them, both animals and divine beings, and the parts of these. All these are called substance because they are not predicated of a subject
Book V Chapter 92015-06-01
The same means (1) that which is the same in an accidental sense, e. g. the pale and the musical are the same because they are accidents of the same thing, and a man and musical because the one is an accident of the other; and &lsq
Book V Chapter 102015-05-31
The term opposite is applied to contradictories, and to contraries, and to relative terms, and to privation and possession, and to the extremes from which and into which generation and dissolution take place; and the attributes that cannot be present at the same time in that which is r
Book V Chapter 112015-05-31
The words prior and posterior are applied (1) to some things (on the assumption that there is a first, i. e. a beginning, in each class) because they are nearer some beginning determined either absolutely and by nature, or by reference to something or in some place or by c
Book V Chapter 122015-05-30
Potency means (1) a source of movement or change, which is in another thing than the thing moved or in the same thing qua other; e. g. the art of building is a potency which is not in the thing built, while the art of healing, which is a potency, may be in the man healed, but not in him
Book V Chapter 132015-05-30
Quantum means that which is divisible into two or more constituent parts of which each is by nature a one and a this. A quantum is a plurality if it is numerable, a magnitude if it is a measurable. Plurality means that which is divisible potent
Book V Chapter 142015-05-29
Quality means (1) the differentia of the essence, e. g. man is an animal of a certain quality because he is two-footed, and the horse is so because it is four-footed; and a circle is a figure of particular quality because it is without angles,-which shows that the essential differentia
Book V Chapter 152015-05-29
Things are relative (1) as double to half, and treble to a third, and in general that which contains something else many times to that which is contained many times in something else, and that which exceeds to that which is exceeded; (2) as that which can heat to that which can be heat
Book V Chapter 162015-05-28
What is called complete is (1) that outside which it is not possible to find any, even one, of its parts; e. g. the complete time of each thing is that outside which it is not possible to find any time which is a part proper to it. -(2) That which in respect of excellence and goodness ca
Book V Chapter 172015-05-28
Limit means (1) the last point of each thing, i. e. the first point beyond which it is not possible to find any part, and the first point within which every part is; (2) the form, whatever it may be, of a spatial magnitude or of a thing that has magnitude; (3) the end of each thing (and
Book V Chapter 182015-05-27
That in virtue of which has several meanings:-(1) the form or substance of each thing, e. g. that in virtue of which a man is good is the good itself, (2) the proximate subject in which it is the nature of an attribute to be found, e. g. colour in a surface. That in virtue of whic
Book V Chapter 192015-05-27
Disposition means the arrangement of that which has parts, in respect either of place or of potency or of kind; for there must be a certain position, as even the word disposition shows.
Book V Chapter 202015-05-26
Having means (1) a kind of activity of the haver and of what he has-something like an action or movement. For when one thing makes and one is made, between them there is a making; so too between him who has a garment and the garment which he has there is a having. This sort of having,
Book V Chapter 212015-05-26
Affection means (1) a quality in respect of which a thing can be altered, e. g. white and black, sweet and bitter, heaviness and lightness, and all others of the kind. -(2) The actualization of these-the already accomplished alterations. -(3) Especially, injurious alterations and movement
Book V Chapter 222015-05-25
We speak of privation (1) if something has not one of the attributes which a thing might naturally have, even if this thing itself would not naturally have it; e. g. a plant is said to be deprived of eyes. -(2) If, though either the thing itself or its genus would naturally
Book V Chapter 232015-05-25
To have or hold means many things:-(1) to treat a thing according to ones own nature or according to ones own impulse; so that fever is said to have a man, and tyrants to have their cities, and people to have the clothes they wear. -(2) That in which a thing