 Spinoza's thought stands at an uneasy and volatile period in the development of physical theory. His physical science is largely Cartesian, both in content and rationalistic method. It is harshly dismissive of the “occult qualities, intentional species, substantial forms, and a thousand other trifles” (letter 60, to Boxel) of pre-revolutionary scholastic natural philosophy. It is likewise antagonistic to the new Baconian experimentalism, holding that empirical findings can at best present examples of what reason itself demonstrates.   Spinoza neither perceives the particular difficulties for Cartesian physical theory that lead Leibniz to revive both finalism and substantial forms, nor foresees the Newtonian theory of universal gravitation whose mathematical and empirical superiority to the Cartesian vortex theory lead to its universal acceptance, despite its own revival of occult powers in the form of forces operating at a distance.