- Rethinking Spinoza in light of the Principle of Sufficient Reason promises to be important not only for our understanding of Spinoza, but also for our understanding of the philosophical issues Spinoza deals with and that continue to trouble philosophers today.
One: Spinoza’s Understanding and Understanding SpinozaEdit
- The purity of Spinoza’s commitment to explanation can best be articulated in terms of his commitments to the Principle of Sufficient Reason (hereafter, the “PSR”) and to his naturalism.
- Spinoza’s own view is one according to which human beings and the rest of reality are not explained in such different ways, according to which human beings and all else operate according to the same laws. Such a unification of explanatory principles is the heart of Spinoza’s naturalism about psychology: human psychology is governed by the same fundamental principles that govern rocks and tables and dogs. Thus no new principles are needed to explain human psychology beyond those principles needed to explain the rest of nature anyway. More generally, Spinoza’s naturalism, as I understand it, is the view that there are no illegitimate bifurcations in reality.
- Spinoza can be seen as a pure philosopher, always seeking explanation, always refusing to be satisfied with primitive, inexplicable notions. This purity is most evident in his commitment to the principle that each fact has an explanation, that for each thing that exists there is an explanation that suffices for one to see why that thing exists. Although Spinoza does not himself use the term, this principle is known as the Principle of Sufficient Reason (PSR).
- According to Spinoza’s system, all reality flows with strict necessity from the nature of God. With the geometrical method, Spinoza captures the structure of this reality by deducing philosophical conclusions about reality from definitions which express the nature of God.
Two: The Metaphysics of SubstanceEdit
- How many things are there in the world? Spinoza’s answer: one.
- I think that one who appreciates the fact that, if there are to be genuine causal connections, they must amount to conceptual connections, is Hume. Hume, of course, denies that there are conceptual connections among distinct things and so he is unable to come up with genuine cases of causation. But, in a way, Hume does accept the rationalist demand that, if there is to be genuine causation, it must amount to conceptual connection. Spinoza accepts this rationalist demand too. But, unlike Hume, he sees there as being genuine conceptual connections, i.e. causal connections, in the world.
- Unsurprisingly, then, Spinoza has not solved the mind-body problem. But he has advanced our understanding of it. He has shown how, if one skillfully and consistently wields the PSR and the conceptual barrier between thought and extension, one can construct an argument for the view that there is one substance and one can undermine the Cartesian intuitions that material things and physical things cannot be identical.
- Spinoza’s metaphysics is, in many ways, an effort to tap into the underlying rationalist motivations of Descartes’s metaphysics and to follow through on these motivations more consistently than Descartes ever did. Employing the Cartesian notions of substance, attribute, and mode, and wielding strongly rationalist principles only hinted at in Descartes—such as the PSR and the Principle of the Identity of Indiscernibles—Spinoza is able to mount a powerful argument for substance monism, for the view that there is, fundamentally, only one thing in the world.
Three: The Human MindEdit
- Spinoza’s parallelism embodies in many ways a deeply anti-Cartesian view. By keeping the causal chains of modes of extension somehow separate from the causal chains of modes of thought, Spinoza is guided by his overarching denial of any explanatory connections between the mental and the physical, i.e. of connections of the kind that Descartes, in his account of mind-body interaction, quite happily embraces. But precisely because Spinoza separates the causal chains in this way, there might be thought to be a crucial point of agreement between Descartes and Spinoza on the nature of mind-body relations.
- As always with Spinoza, it is helpful to begin with God. The system of ideas that are parallel to modes of extension constitutes God’s infinite intellect.
- For Spinoza, obviously, the human mind, as well as the human body, are individuals (actually, they are the same individual). However, this individuality of the human mind would be threatened if the human mind were made up of ideas whose contents were relatively disparate, if these ideas were not all focused around a particular unified thing, such as the human body.
- Spinoza’s naturalism and rationalism are nowhere more evident and more relevant to contemporary philosophy than in his philosophy of mind. All there is to thought is the having of ideas, representations of certain things. Thus, in laying down requirements on what it is to have an idea or representation of an object, Spinoza is articulating the essence of the mental.
- For Spinoza, my mind is simply an idea in God’s intellect; in particular it is God’s idea of my body.