Under the first head come questions of Fact; under the second head, questions of Cause or Reason; under the third, questions of Existence; under the fourth, questions of Essence. Under the first head we enquire, Whether a fact or event is so or so? Whether a given subject possesses this or that attribute, or is in this or that condition? enumerating in the question the various supposable alternatives. Under the second head, we assume the first question to have been affirmatively answered, and we proceed to enquire, What is the cause or reason for such fact, or such conjunction of subject and attribute? Under the third head, we ask, Does a supposed subject exist? And if the answer be in the affirmative, we proceed to enquire, under the fourth head, What is the essence of the subject?[1] [Footnote 1: Analyt. Post. II. i. p. 89, b. 23, seq. Themistius observes, p. 67, Speng.: [Greek: zêtou=men ti/nun ê)\ peri\ a(plou= tino\s kai\ a)sunthe/tou, ê)\ peri\ sunthe/tou kai\ e)n prota/sei.] Themistius has here changed Aristotle's order, and placed the third and fourth heads before the first and second. Compare Schol. p. 240, b. 30; p. 241, a. 18. The Scholiast complains of the enigmatical style of Aristotle: [Greek: tê=| griphô/dei tou= r(êtou= e)paggeli/a] (p. 240, b. 25).] We have here two distinct pairs of _Quæsita_: Obviously the second head presupposes the first, and is consequent thereupon; while the fourth also presupposes the third. But it might seem a more suitable arrangement (as Themistius and other expositors have conceived) that the third and fourth heads should come first in the list, rather than the first and second; since the third and fourth are simpler, and come earlier in the order of philosophical exposition, while the first and second are more complicated, and cannot be expounded philosophically until after the philosophical exposition of the others. This is cleared up by adverting to the distinction, so often insisted on by Aristotle, between what is first in order of cognition relatively to us (_nobis notiora_), and what is first in order of cognition by nature (_naturâ notiora_). _To us_ (that is to men taken individually and in the course of actual growth) the phenomena of nature[2] present themselves as particulars confused and complicated in every way, with attributes essential and accidental implicated together: we gradually learn first to see and compare them as particulars, next to resolve them into generalities, bundles, classes, and partially to explain the _Why_ of some by means of others. Here we start from facts embodied in propositions, that include subjects clothed with their attributes. But in the _order of nature_ (that is, in the order followed by those who know the _scibile_ as a whole, and can expound it scientifically) that which comes first is the Universal or the simple Subject abstracted from its predicates or accompaniments: we have to enquire, first, whether