The Unity of the Speculative and Practical Intellect

[St. Thomas Aquinas] made the – really quite brilliant – [observation that] what distinguishes human understanding is precisely the ability to come to know things as they are. And it’s from the knowledge of the way the things are that practical knowledge follows. So there’s not just a split between speculative and practical, there’s a sequence: The human intellect comes to understand things, and on the basis of what it understands becomes able to exercise control over what is understood. [1]

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Footnotes:

1. Aquinas’ phrase that “the speculative intellect by extension becomes practical” (“intellectus speculativus per extensionem fit practicus”) is from Summa theologiae, Prima Pars, Quaestio 79, Articulus 11, sed contra, cf. Aquinas c1252-73, and is a paraphrase of Aristotle’s statement (De anima, II, 10 433a 15) that “the practical intellect [...] differs from the speculative intellect by the end at which it aims” (“(intellectus) speculativus differt a practico, fine”), cf. Aristotle c350 AC.

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Source: John Deely, interviewed by Morten Tønnessen, "Tell Me, Where Is Morality Bred? The Semioethics Interviews I: John Deely," Hortus Semioticus 4 (April 7, 2009): 54, accessed March 1, 2014, http://www.ut.ee/hortussemioticus/4_2009/pdf/hortussemioticus_4_deely.pdf.