things—that is, their essences—without regard to their existence outside the mind. The mistaken thinker therefore imagined that these realities and essences had an established reality outside the mind.

The truth is that all of this is established in the mind. What can be conceived in the mind is broader than what actually exists outside it. It exists and is established in the mind; it is not, in fact, devoid of both existence and established reality. Thus, distinguishing between existence and established reality, or between existence and essence, while claiming that both are outside the mind, is a grave error.

These people supposed that the realities of species, such as the reality of the human being, the horse, and the like, were established outside the mind, distinct from the individual entities existing there, and that they were without beginning and incapable of change. These are what are called “Platonic Forms.” Nor did they stop there: they also asserted the same concerning matter, essence, and place. They posited matter stripped of forms, established outside the mind: this is the prime matter on which they based their doctrine of the eternity of the world. The majority of rational thinkers judged them mistaken on this point.

The views of those who distinguish between existence and essence are discussed at length elsewhere. The purpose here is to draw attention to the fact that the distinction they make in logic between an essence and its existence outside the mind rests on this unsound principle. The proper distinction is that essence is the impression of a thing formed in the mind, whereas existence is what there is of that thing outside the mind,