Interesting Quote From Thomas Aquinas (Summa Contra Gentiles I.4)

"owing to the infirmity of our judgement and the perturbing force of imagination, there is some admixture of error in most of the investigations of human reason" (Thomas Aquinas, SCG I.4).

Thomistic Souls Versus Cartesian Souls

Thomas Aquinas considers the soul to be subsistent, but not in the Cartesian sense. Kevin Corcoran quotes Summa Contra Gentiles II.69 to demonstrate this point: "body and soul are not two actually existing substances; instead, one actually existing substance arises from these two" (See Rethinking Human Nature, 38). So it's the human person (body and soul) that constitutes one thing or two incomplete substances for Aquinas and those who follow in his wake.