Despite the widely advertised claims of France and England as the sources of Enlightenment, there is no doubt that its radiance derived from the Dutch Spinoza (1632-1677), who raised damagingly unanswerable questions about the validity of theology. Spinoza challenged received ideas about God. Central to Hebraic and Christian doctrines are the miracles and the casting out of devils. By alleging that God and nature were two names for the same thing, Spinoza made clear that witches and devilish forces pertained to a supernatural that was a logically impossible domain. Devils and angels could not exist because nothing could be outside God, who is Nature. Belief in miracles was a symptom of unreasonable ignorance. Spinoza did not deny the existence of God but asserted that a specific God, be He Christian, Hebraic or Muslim, was spurious. Spinoza was not only a philosopher but also a practical scientist. Claiming that reason and intellect do the real work, proceeding on the basis of experiment, he prefigured Karl Popper, for whom the scientific theories precede the experiments that may prove or disprove them. Human progress depends on the primacy of rational ideas, not on the accumulation of experimental data. Spinoza emphasized that what is important is not doing the sums right but doing the right sums.
Spinoza preferred practical remedies for practical problems. Abstract principles are no substitute for practical-minded engagement of the subject under investigation. His humane approach to the understanding of the world by the application of reason tempered by observation was waved on the side by the undue influence of mechanics and abstract mathematical methods on the received idea of what intelligent problem-solving should be. Deduction in the style of Euclid, mechanically predictable and rigorous laws in the style of Galileo and Newton, indubitable certainty in the style of Descartes exerted a malign influence insofar as they overshadowed a looser, more pragmatic and less abstract concept of reasonableness. The damage was inflicted by Newton (1642-1727), whose dynamic came to be regarded as the ideal model to which all forms of rational thinking should aspire. But the greatest damage was inflicted a century later by Laplace (1749-1827). According to Laplace, the universe was strictly deterministic and, following his lead, all sciences became unadvisedly modeled on mathematical physics. Inappropriate mathematical rationality was preferred over open-minded and informal reasonableness, with dramatic results on progress in humanness (fig. 14.8).
Figure 14.8. In the 16th century, the Flemish Th. Van Thulden painted the victory of wisdom over stupidity, which brings abundance. Today, he would have painted the contrary.