“Spinoza’s (1632—1677) Ethics starts with a clear framework, explanation, and definition of his terms. In that way, the philosophical inquiry becomes more accessible and precise for a reader or interpreter to understand and grasp. When Spinoza, in his definitions, uses the term substance, we understand that it is God. But when the term substance reappears under point III and then again under VI, which treats God, we must question why. For Spinoza, there is substance and substance. What is the difference between the substance under III and VI? We would say that, according to Spinoza, the ultimate, infinite substance is God, and everything formed is of the same substance. If that is the case, all substance is God or Nature. If all substance is God, then the question is, why separate substance from substance?

Spinoza wanted to highlight the difference between the infinite substance of the ultimate Being, God, and the substance that makes Nature in all its forms. But nature, or anything in nature, is substance “which is in itself and is conceived through itself and does not need another “thing” to form it.” Nature is just a manifestation or mode of God or Substance.

Substance (substantia) is not a new term and has been used since Aristotle, if not earlier. Perhaps the substance is interchangeable with terms like arche, aether …. fifth element, proton archon (first principle), Plotinus’ Divine mind (nous), or intelligence. Here are Spinoza’s definitions:

Of God
DEFINITIONS

I. By cause of itself I understand that whose essence involves existence, or that whose nature cannot be conceived unless existing.

II. That thing is called finite in its own kind (in suo genere) which can be limited by another thing of the same nature. For example, a body is called finite because we always conceive another which is greater. So a thought is limited by another thought; but a body is not limited by a thought, nor a thought by a body.

III. By substance I understand that which is in itself and is conceived through itself; in other words, that the conception of which does not need, the conception of another thing from which it must be formed.
IV. By attribute I understand that which the intellect perceives of substance as constituting its essence.

V. By mode I understand the modifications of substance, or that which is in another thing through which also it is conceived.

VI. By God I understand Being absolutely infinite, that is to say, substance consisting of infinite attributes, each one of which expresses eternal and infinite essence.”