Man is said to be his own intellect, not because the intellect is the entire man, but because the intellect is the chief part of man, in which man's whole disposition lies virtually
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic intellect lie
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/19950/pg19950-images.html

Context

“and the result of this assumption was that God is man, and man is God. But this assumption did not cease by the separation of the Word from the soul or from the flesh; yet the union of soul and flesh ceased. Reply Obj. 2: Man is said to be his own intellect, not because the intellect is the entire man, but because the intellect is the chief part of man, in which man's whole disposition lies virtually; just as the ruler of the city may be called the whole city, since its entire disposal is vested in him. Reply Obj. 3: That a man is competent to be a priest is by reason of the soul, which is the subject of the character of order:” source