Given that each kind of being is divided into that which is in actuality, and into that which is in potentiality, the actualization of that which is in potentiality, in so far it is such, is change, e.g. the actualization of that which is capable of altering, in so far it is such as to be capable of altering, is alteration, of that which is capable of increasing and its opposite, that which is capable of decreasing (there is no common name for both of them), increase and decrease, of that which is capable of coming to be and passing away, coming to be and passing away, of that which is capable of being carried along, locomotion.
That this is change is clear from this. For when that which is capable of building, in so far it is said to be such, is in actuality, it is being built, and this is building; and similarly with learning and doctoring and rolling and jumping and maturing and ageing.
Six kinds of change
There are six kinds of change: generation, destruction, increase, decrease, alteration, change of place. That the other changes are distinct from one another is obvious; for generation is not destruction, nor yet is it that increase is decrease or that the change of place is so, and likewise with the others too; but as for the alteration, there is a question, whether it is not perhaps necessary for what is altering to be so doing in respect of one of the other changes.
But this is not true; for in pretty well all cases of affections, or in most of them, we happened to undergo alteration without partaking of any of the other changes; for what is affected does not necessarily increase or decrease — and similarly with the others. Hence, alteration would be distinct from the other changes; for if it were the same, the thing altering would at once have to be increasing or decreasing, or one of the other changes would have to follow; but this is not necessary.
Bibliography: Aristotle Physics, Categories
Translation – text editing: George Kotsalis