Popper and Spinoza. The Enlightenment that Failed.

I was studying Popperʼs works these days and have been rather intrigued by the fact that Popper does not discuss Spinozaʼs natural monism, while he deals with Parmenides and considers his theory “the first hypothetical-deductive method of the world” (Conjectures and Refutations, Routledge, 1963, 2002, p. 196), and admires him highly; but he says nothing of the most famous hypothetical-deductive method in the history of philosophy, as it is stated in Spinozaʼs Ethics. I think Popper feared the stigma of sympathizing with the Radical Enlightenmentʼs most vilified philosopher by religious people, for he talks much about Newton, Voltaire, and Kant, the three of which held some kind of moderate Enlightenmentʼs position with regard to reason and faith. Kant, in fact, held that there would never be a science of human behavior, something that Evolutionary Psychology refutes today. Popper seems to defend Christianity at every turn in his The Open Society & Its Enemies, something that goes against the registered facts of History. It is a scandal today to read how Christians defended kings and aristocrats against democracy and tolerance. Bertrand Russell does not fear to speak up where Popper stays quiet.

After reading Jonathan Israelʼs sixth and final book of his series on the Enlightenment (The Enlightenment that Failed, Oxford University Press, 2020, with A Revolution of the Mind as a brief exposition of his theory), I have gained a wide perspective of how important Spinoza was and is for the history of philosophy, specially considering his naturalist monism, with matter being active and non-teleological, thus in accord with evolution by natural (and sexual and kin) selection. It is highly important to note how our present philosophers hide this fact, or ignore it. I mean the fact that Spinoza is the most influential philosopher of the Radical Enlightenment that created our present world of democracy and tolerance, reason and science. If Evolutionary Psychology shows us something, that is that naturalist monism is the view of science today, thus showing again that Spinoza was right, and Kant, Voltaire, and Newton were wrong (the three of them believed in intelligent design by God, the so-called Physico-Theology philosophy, separating humans from nature). In The Adapted Mind (Oxford University Press, 1995, pp. 21-22) we read that this perspective has been abolished:

The rich complexity of each individual is produced by a cognitive architecture, embodied in a physiological system, which interacts with the social and nonsocial world that surrounds it. Thus humans, like every other natural system, are embedded in the contingencies of a larger principled history, and explaining any particular fact about them requires the joint analysis of all the principles and contingencies involved. To break this seamless matrix of causation—to attempt to dismember the individual into “biological” versus “nonbiological” aspects—is to embrace and perpetuate an ancient dualism endemic to the Western cultural tradition: material/spiritual, body/mind, physical/mental, natural/human, animal/human, biological/social, biological/ cultural. This dualistic view expresses only a premodern version of biology, whose intellectual warrant has vanished.

As Spinoza said centuries before. In fine, considering Popperʼs evolutionary epistemology, Spinozaʼs absence from Popperʼs analysis seems surprising. Popper ignores the Radical Enlightenment altogether, writing that Voltaireʼs Letters Concerning the English Nation published in 1733 pleading for toleration “marks the beginning of a philosophical movement—a movement whose peculiar mood of intellectual aggressiveness was little understood in England, where there was no occasion for it” (Ibid., p. 238). Popper not only ignores Spinozaʼs plead for toleration in his Tractatus Theologico-Politicus published in 1670, but does not even comment that Voltaire was not a radical Enlightener, but a mainstream one, that is: Voltaire was a deist who was in favour of kings and aristocracy, was against democracy and equality of rights, and defended the intelligent design of God against Diderotʼs and DʼHolbachʼs naturalist monism, following Spinozaʼs system here. That is what happens when you read the six great Jonathan Israelʼs magnificent books on the Enlightenment: that no one can fool you easily by hiding important issues on the Enlightenment anymore.