Baruch (aka Benedict, aka Benedictus) Spinoza was a truly great philosopher. Professor Hampshire’s introduction to Spinoza, first published in 1951, has been one of my favorite books since I first read it in the 1970s. So it was disappointing to read this collection of Hampshire’s writings on Spinoza and find it rather tedious, mainly due to the repetitive nature of the book’s three main sections.
Still, if you want to understand Spinoza, Hampshire’s Spinoza: An Introduction to His Philosophical Thought, the 1987 edition of which is included in this book, is an excellent place to start.
Spinoza famously argued that there can only be one infinite substance. This is Deus sive Natura, God or Nature. There is nothing supernatural about God, since God and Nature are the same. This one substance has two attributes, so far as we know: thought and extension, or mind and matter. Everything that exists or occurs is represented in both of these attributes. When something happens in my body, it also happens in my mind, and vice versa (although sometimes unconsciously). The same rule applies to all other objects in the universe, e.g. both rocks and rabbits.
In addition, everything that happens is fully determined. If we had the mental capacity, we could infer everything about the universe from what happened before. Yet we human beings have moments of freedom, i.e. when we exercise our rationality, either in pursuits like mathematics or in understanding ourselves and the world around us.
Hampshire doesn’t accept everything Spinoza said, of course. But he does generally endorse Spinoza’s view of our “double aspect” and what it means to be free in a deterministic world. Unfortunately, it’s hard to understand what it means for a rock to have a mental aspect. Hampshire tries to explain this idea by suggesting that a rock’s thought-like aspect is its form: “they have a nature and form which can be described or represented. They are not a haphazard collection of atoms. They have their own distinctive unity.”
But I think Spinoza was closer to the truth regarding the “mental” aspect of people and other animals than he was about things like rocks or trees. We have both a form that can be represented and the ability to represent ourselves and other things. We have evolved and become aware (Hampshire doesn’t disagree, of course). Having a form and being able to represent something that has a form are quite different things, although perhaps that’s what Spinoza had in mind. A rock has something that can be represented by an idea. And we have ideas. So maybe we are just a bit higher on the evolutionary scale.