No doubt, the spirit of the early modern science had a great impact on Spinoza’s cast of mind. But the pre-eminent aspect of this influence is not the one the victories of the mechanical sciences had on the conception of causation and of the nature of bodies; rather, it is the effect the new mathematical understanding of the realm of nature had on Spinoza’s deepest assumptions concerning the way in which all genuine things are built, or how the basic nature of their being is determined. A clear grasp of these commitments will later prove vital for understanding Spinoza’s way of thinking about power and related topics.

It is not only in the Ethics that Spinoza tackles fundamental ontological questions; we have much to gain from his early works. Metaphysical Thoughts (published in 1663) is an especially relevant tract for our purposes, for its first part discusses the question of being and the way it should be classified. The work is an appendix to a presentation of Descartes’s Principles of Philosophy in the geometrical manner, and it is not always completely clear to what extent Spinoza is voicing his own views; but I believe that especially the first two chapters of the opening part of the Metaphysical Thoughts deserve to be read very carefully. The other two early works I will take up are the Treatise on the Emendation of the Intellect (c. 1661) and the Short Treatise on God, Man, and His Well-Being (c. 1662, discovered in the nineteenth century). In the latter section of this chapter, I will discuss the way in which the ideas expressed in these works are further elaborated in the Ethics.