Spinoza was the most rigorous and systematic of the major rationalist philosophers. Where Descartes was confident that reason would vindicate the main tenets of his Catholic faith, Spinoza dared to follow reason into religiously more treacherous territory. Spinoza is alternately described as the “God intoxicated Jew” and as a heretical atheist. Spinoza’s family had fled the Inquisition in Portugal for the relative religious tolerance of Amsterdam. At the age of 23, however, Spinoza was excommunicated from his Jewish synagogue for holding heretical beliefs. Spinoza knew religious persecution both as a member of a community of faith, and then as an individual cast out of a community of faith. Perhaps not surprisingly then, he becomes an early advocate for freedom of conscience and religious belief in his political writings.
Spinoza supported himself as a lens grinder until his early death at the age of 46. While he demonstrated immense courage in the face of excommunication and in philosophically challenging religious doctrines, he led a fairly quiet and reclusive life devoted to study and work in a state of relative poverty. His views were widely considered so threatening to established religion that his considerable influence went largely unacknowledged for a century or two after his death. Still, the next most significant thinker of this period after Descartes, Liebniz, is now seen by some as devising his philosophical system as an attempt to protect religious belief from the intellectual threat of Spinozism.
Descartes’ method of doubt sets him on the project of finding epistemological foundations for knowledge. Descartes seeks to identify some knowledge as foundational in the sense of being able to justify the rest of our knowledge. By contrast, we might best understand Spinoza as seeking metaphysical foundations. Suppose the world is intelligible, that its nature can be understood rationally. Assuming this, what must the world be like? We might worry that this approach simply sidesteps epistemological worries about how we can know. But suppose that in exploring the assumption that the world is intelligible we find that all but one view about the nature of the world gets us mired in contradictions or intractable problems. We would then have grounds to accept the one coherent metaphysical account of the nature of the world as an instance of inference to the best (or perhaps, the only) explanation. Seeking coherent systematic explanation can, ultimately, yield justifying reasons.
This is just a suggestion for how to understand what Spinoza is up to in his masterpiece The Ethics. This strategy is not made explicit in the work itself. Rather, Spinoza’s Ethics is written in a geometric style. He begins with a few definitions and axioms and the work proceeds by deductively proving an impressive array of further propositions. The propositions derived from his initial definitions give an account of God, the natural world (these turn out to be the same thing), the self, the nature of human freedom, the nature of the emotions, and the nature of the good life in-so-far as it is attainable for beings like ourselves. We might say of the entire system that it is elegantly consistent. But why accept its starting points? His initial definitions and axioms might strike us as arbitrary or even implausible (though his contemporaries would have found them pretty reasonable). The case for the system as a whole is that it is elegant and consistent while the alternatives are not. The axioms and definitions are not just arbitrarily preferred starting places; they are the starting places that allow us to give a clear coherent picture of God, the world, and the human condition.
It would help to see how Spinoza might make this case by understanding how his view of the world is offered in response to an alternative, Descartes’, which did seem to lead to intractable problems. Recall Descartes’ dualism, his view that the world contained two fundamentally different kinds of substance: matter and mind. The difficult problem for this view was to give some account of how mind and matter could interact in spite of being so different. But however that problem is to be solved, there is something further to be noticed. Any kind of mind body interaction will perforce involve mutual limitations on each. If through a mental act of will I cause some change in the material realm, then the material realm is limited in that it can’t be other than I have willed it. Likewise, if the material world has some effect on my mind, then my mind is similarly limited.
Now consider the idea of God. Spinoza defines God as a being that is infinite, where being infinite entails being unlimited. The only way that any substance could be absolutely unlimited is for there to be no other substances that could possibly limit it. So, argues Spinoza, there is only one substance and it is both God and nature. Every facet of the world is a mere part of this one substance, God/nature. And everything we do and experience is a limited manifestation of the essence of God. Every aspect of our lives, everything we think and do, is an expression of God/nature’s essence which is uncaused and necessary. For this reason, nothing we do or experience could possibly be any different. This settles the matter of free will, though not quite it the way Descartes would hope.
Our perception of the world as including many distinct things and minds other than our own is a confusion of ours, or, as Spinoza would put it, an “inadequate idea.” The true nature of the world is singular. There is only one thing in existence, and it is both God and all of nature. God/nature being the one existing substance is self-sufficient. Since it depends on nothing and is affected by nothing, everything about God/nature is necessary. God/nature, being infinite and perfect in all respects, has an infinite number of aspects, or attributes. Our existence as human beings presents us with only two of these, the attribute of thought and the attribution of extension (physical spatio-temporal existence).
While thought and extension, which we experience as mind and body, are attributes of God, our idea that there is some interaction between the two is a further confusion according to Spinoza. The mind and the body are really one and the same. We are limited modification of God/nature. One of the ways we are limited is in only being aware of two of the infinite attributes of God, thought and extension. The idea that the mind and the body are different and interact is a confusion of ours that we suffer due to thinking of ourselves sometimes under one attribute, thought, and at other times under another, extension. In thinking about ourselves, we are in position much like Joe who thought of a particular individual in one way, as Mark Twain, and also in a different way, as Samuel Clemens. Spinoza’s view is that mind and body are one and the same limited modification of God, understood on one hand through the attribute of thought and on the other through the attribute of extension. A better way to put this might be to just say that the mind is the idea of the body.
We are finite an imperfect “modes” of the attributes of thought and extension. As such limited and imperfect beings, we see ourselves as separate from many other things. Being ignorant of the causes of things, including the determination of our own wills, we imagine that things might have been otherwise. But everything happens of necessity. So Spinoza’s answer to the problem of free will and determinism is to deny that we have free will. This doesn’t mean, however, that there is nothing to say about how to live well. Living well, according to Spinoza, involves coming to terms with our limitations and the way things must be as a matter of necessity. And the way to do this is through better understanding ourselves, the world (God/nature) and our position in the world. The good life, for Spinoza, is one organized around the intellectual love of God/nature.
There is one kind of freedom that we might aspire to in all of this, and it is the kind of freedom that can be had through the intellectual love of God/nature. The freedom we can have is freedom from the tyranny of our passions, our emotions. Our hopes and fears are passions that make us anxious and insecure when we fail to understand their causes and our own place in nature. A better understanding of the necessity of all things, which for Spinoza is just the intellectual love of God/nature, is the one therapy open to us in addressing the insecurity and anxiety that comes with human vulnerability and mortality. Knowledge of how to live one’s life is established after the manner of a proving a theorem of geometry in Spinoza’s Ethics. Coming to understand his demonstration of how to live well will itself be an exercise in living well.