The “simple one” with which they describe the Necessary Existent is of the same species as the “simple one” they posit as the principle of composites when they say, “Man is composed of animality and rationality, and the analysis comes to rest at a single, simple entity devoid of composition.” Such a “one,” however, exists only in the mind, not in the external world.
Their statement that man is composed of animal and rational, of animality and rationality, can hold only for what the mind conceives; for the conceiver imagines a rational human being, a sentient body that moves by volition and speaks. Each of these so-called parts is merely a part of what he has pictured within himself. The term that denotes the whole signifies the combination by direct indication, its parts by implication, and what necessarily follows from them by entailment. Taken together, they constitute the complete quiddity as conceived in the intellect: whatever lies within that conception is “inside” the quiddity, and whatever lies outside it is “outside.” The essence, then, is only as the mind conceives it; if the intellect pictures a “laughing” human, “laughing” becomes a component of that very quiddity.
As for one who claims that the human being existing externally is composed of such-and-such, his claim is valid only if he means that the being is characterized by those two attributes, that the attributes subsist in him, and that he bears them just as a substance bears its accidents and a subject its properties.
But to assert that the substance itself is composed of accidents, or that it is made up of several substances—one called “body,” another “sentient,” a third “living,” a fourth “moved by will”—and that this particular human being contains multiple substances corresponding to these various names, so that the substance that is sentient is not the very one that is self-moved by volition, nor the one that is body, nor the one that is rational, and that the rational is not the sentient—this is manifestly false once one forms a clear conception of the matter.
The philosophers’ notion of the oneness of the Necessary Existent:
Likewise, the “One” with which they describe the Necessary Existent, claiming that it is stripped of every