View Articles

Monday, May 30, 2011

0175: Remarks on the Principle of Non-Contradiction (V)

Entry 0175: Remarks on the Principle of Non-Contradiction (V)

Remarks by Thomas D. D'Andrea:

“For both Aristotle and Aquinas, the first principle of understanding [is] the metaphysical principle of non-contradiction. Of this, Aristotle says:

the most certain principle of all is that regarding which it is impossible to be mistaken; for such a principle must be both the best known (for all men may be mistaken about things which they do not know), and non-hypothetical. For a principle that anyone must have who understands anything is not a hypothesis… Evidently then such a principle is the most certain of all; which principle this is let us proceed to say. It is, that the same attribute cannot at the same time belong and not belong to the same subject and in the same respect… This then is the most certain of all principles, since it answers to the definition given above. For it is impossible for any one to believe the same thing to be and not to be, as some think Heraclitus says. For what a man says, he does not necessarily believe… (Metaphysics IV, 1 005b12-25, Ross trans.)

“Aquinas glosses these remarks by referring to the principle as ‘the axiom of all axioms’ (Commentary on the Metaphysics of Aristotle, para. 604), and adds that, ‘evidently this principle is not based on an assumption. Indeed, insofar as it is by nature a starting point, it clearly comes unsought to the one having it and is not acquired by his own efforts’ (para. 605). Aquinas can plausibly be taken to hold here that the first principle is embedded (implicit and presupposed) in all human thought as such, from which it does not follow that all humans know that the principle is true (even philosophers such as Heraclitus seem confused about it), or that they know, moreover, that it is necessarily true, and even the most basic of necessary truths (i.e., as the truth presupposed by all other necessary truths).” [1]


[1] Thomas D. D'Andrea, Tradition, Rationality, and Virtue: The Thought of Alasdair MacIntyre, (Aldershot: Ashgate Publishing Company, 2006), 413.