Coming to Essence, this in its epistemological force is that intelligible character which truly defines what a general or indefinite, that is, what an indeterminate monadic predicate primarily asserts, so that all else that it asserts is the necessary consequence of this epistemological essence. It is easy to state what the essences of artificial objects are: The essence of a stove is that it is intended to diffuse warmth. But as to the essence of natural objects, if they have any, we are unable as yet to give them. We are only able to state the essence of our common names for such things. The metaphysical essence is the intelligible element of the possibility of its Being, or so much of that as is not a mere consequence of the rest…
The essence of a thing consists in its being rendered intelligible by being regarded from a certain general point of view. This gives it an intellectual nutritiousness. For instance, I may be shown a complicated piece of machinery, and while recognizing how many parts of it must or may move together, I may be utterly at a loss to understand it, or to discern what kind of a machine it is until someone tells me what purpose it is intended to subserve. Then I see. That I see gives it a function, an office in the world. But the essence does no more than determine the generic mode of being of the thing.
From an alternative draft