But that which is most peculiar to Essence, is, that while remaining _Unum et Idem Numero_, it is capable by change in itself of receiving alternately contrary Accidents. This is true of no other Category. For example, this particular colour, being one and the same in number, will never be now black, and then white; this particular action, being one and the same in number, will not be at one time virtuous, at another time vicious. The like is true respecting all the other Categories. But one and the same man will be now white, hot, virtuous; at another time, he will be black, cold, vicious. An objector may say that this is true, not merely of Essence, but also of Discourse and of Opinion; each of which (he will urge) remains _Unum Numero_, but is nevertheless recipient of contrary attributes; for the proposition or assertion, Sokrates is sitting, may now be true and may presently become false. But this case is different, because there is no change in the proposition itself, but in the person or thing to which the proposition refers; while one and the same man, by new affections in himself, is now healthy, then sick; now hot, then cold.[44] [Footnote 44: Aristot. Categ. p. 4, a. 10-b. 20.] Here Aristotle concludes his first Category or Predicament--Essence or Substance. He proceeds to the other nine, and ranks Quantity first among them.[45] _Quantum_ is either Continual or Discrete; it consists either of parts having position in reference to each other, or of parts not having position in reference to each other. Discrete _Quanta_ are Number and Speech; Continual _Quanta_ are Line, Surface, Body, and besides these, Time and Place. The parts of Number have no position in reference to each other; the parts of Line, Surface, Body, have position in reference to each other. These are called _Quanta_, primarily; other things are called _Quanta_ in a secondary way, [Greek: kata\ sumbebêko/s].[46] Thus we say _much white_, when the surface of white is large; we say, _the action is long_, because much time and movement have been consumed in it. If we are asked, _how long the action_ is? we must answer by specifying its length in time--a year or a month. [Footnote 45: Ibid. b. 21, seq.] [Footnote 46: Ibid. p. 5, a. 38, seq.] To _Quantum_ (as to Essence or Substance) there exists no contrary.[47] There is nothing contrary to a length of three cubits or an area of four square feet. Great, little, long, short, are more properly terms of Relation than terms of Quantity; thus belonging to another Category. Nor is _Quantum_ ever more or less _Quantum_; it does not admit of degree. The _Quantum_ a yard is neither more nor less _Quantum_ than that called a foot. That which is peculiar to _Quanta_ is to be equal or unequal:[48] the relations of equality and inequality are not properly affirmed of anything else except of _Quanta_. [Footnote 47: Ibid. b. 11, seq.] [Footnote 48: Ibid. p. 6, a. 26-35.]