Questions on the Metaphysics of Aristotle

Question Three

QUESTION THREE Text of Aristotle: “The most certain principle of all is that regarding which it is impossible to be mistaken.” (ch. 3, 1005b 1112 ) “The same attribute cannot at the same time belong and not belong to the same subject and in the same respect. We must presuppose, to guard against logical objection, any further qualifications that might be added. This then is the most certain of all principles.” (Ibid., 18-21). Is this principle “It is impossible for the same thing simultaneously to be and not be” the firmest of all? [Arguments Pro and Con] 1 [1] That it is not: [a] First because it is false and [b] also because another is better known and [c] also because one can doubt about it. Proof of the first: opposites can be in the same thing; therefore, contradictories, since they are included in others which can be contraries, Topics II:1 ‘To everything in which there is a genus, there is also a species’, whether it be in essential or denominative predication. But a shield that is half white and half black is colored; therefore, it is denominated by some species of color; by the whiteness and by the same token by blackness; therefore, it is a t the same time both white and black. 2 And so it is with contraries of relative opposites. This is the double of that; therefore, it is double; the opposite of the consequent cannot stand with the antecedent; therefore a simili; this is half of that; therefore, this is half; therefore, the same thing is double and half. 3 Also, some inference is good in which the opposite of the consequent does not imply the opposite of the antecedent; therefore, etc. Proof of the antecedent; both in what is uniform about the contingent, and in other instances, ‘the stone sees; therefore, 1 Aristotle, Topics II, ch. 4, 111a 33-35. 318 THE METAPHYSICS OF JOHN DUNS SCOTUS something having eyes sees’; however from the opposite of the consequent it is not valid. To the issue at hand: if the opposite of the consequent does not imply the opposite of the antecedent, then it can stand in truth with the antecedent, and with what the antecedent stands the consequent also stands, and thus we have simultaneously the consequent and its opposite. 4 As for the second [b], namely that something is better known than this principle. Proof: In Bk. IV of this work:2 An affirmative statement is better known than its negation; but this [the principle of contradiction] is negative. 5 Also, in the syllogism from opposites the conclusion must be better known in its falsity than the principles themselves; but the conclusion denies the same thing of itself; in the premises the opposites are taken; therefore, it [the conclusion] is better known. 6 Also, one can doubt it. Proof: all cognition has its origin in the senses;3 but one can err regarding all sense cognition; therefore, also regarding intellectual cognition one [can err]. 7 Also, one can know in general and be ignorant of the particular; in Prior Analytics II,4 so that one can opine the opposite in particular, but that is the contradictory of what is known; as every mule is sterile, and some [mule he sees and thinks to be with foal] is not; therefore one can opine contradictories. 8 [2] For the opposite there is the Philosopher, because of the three conditions:5 [1] that one cannot doubt it; [2] that it is not a conditional; [3] that it is a principle everyone must have. [I.—STATE OF THE QUESTION] 9 These are the conditions of a most certain or firm principle. Proof of the first according to the Commentator:6 One cannot doubt it, because if one did, he could think that contraries were in the same thing, for instance, that the same thing is both hot and cold. 2 Aristotle, Metaphysics IV, ch. 4, 1008a 17-18. 3 Aristotle, Posterior Analytics, I, ch. 18, 81b 6-9. 4 Aristotle, Prior Analytics, II, ch. 21, 67a 26-38. 5 Aristotle, Metaphysics IV, ch. 3, 1005b 12-18. 6 Averroes, Metaphysica IV, com. 9, f. 36ra. BOOK IV QUESTION THREE 319 10 Proof of the second, that it is non-conditional: because a l l propositions are reduced to it. 11 Also it is the principle of all the axioms. Therefore, it cannot be...