For the class in Modern Philosophy I'm taking this semester, we have to write 15 two-paged papers (minimum) on philosophers such as Descartes, Hume, Locke, and Leibnitz. In this essay, I wrote about Leibniz's prefatory response Locke's Essays. The following is my submission:
While Leibniz regularly praised Locke and at times noted that he and Locke did not disagree – examples: God can do things which men do not comprehend; reliance on divine revelation alone is epistemologically unnecessary; etc. – in his prefatory response to Locke’s “Essays Concerning Human Understanding,” Leibniz’s goal was to clearly distinguish, in general terms, his Platonic philosophy from Locke’s Aristotelian philosophy. Several acute criticisms Leibniz advanced against Locke’s system are as follows:
Locke’s assertion that our mind is a blank slate clearly did not sit well with Leibniz. If all truth is derived extrinsically, Leibniz wrote, it would be impossible to validly generalize necessary truths (such as logic, metaphysic, and ethics) from a finite number of experiences. Anticipation of a repeated event based on memory of what one perceives to be a similar precursor is certainly not irrational, but it is also not, as Leibniz pointed out, an infallible expectation. While sensation can provide the occasion for the reflection and confirmation of these truths – some of which Locke must presuppose in his own argumentation – it cannot be the ground for them. In fact, Leibniz believed that Locke was conflicted about this issue, as he cited that Locke admitted some ideas originate in reflection rather than sensation. Whether Locke realized it or not, to state reflection is an attention to something within oneself which has not been produced by sensation undermines the idea all truth is learned experientially.
The relation between one’s soul and body was another disagreement Leibniz had with Locke. As a self-professed Cartesian – at least in this matter – Leibniz believed in the doctrine of concomitance. He thought that all men’s souls naturally possesses a body. Several of Locke’s beliefs clashed with this. For example, when Locke wrote that matter can think, Leibniz objected that such would require continuous miraculous intervention, as such would unnatural. Leibniz argued that the fact God can do things which men do not comprehend does not in turn imply we can’t recognize impossibilities, and speaking of God, Leibniz used His [immaterial] existence to further support his argument that matter is not a precondition of thought. Another example of a way in which Locke’s anthropological views varied from Leibniz’s stems from Locke’s belief that souls can cease to think in an analogous manner bodies which cease to move. Leibniz accused Locke of question-begging on two accounts: firstly, in that bodies do not, in fact, cease to move, for just because we do not necessarily perceive a rope lengthen past its breaking point does not mean it is not logically necessary that such be the case; secondly, that even if the idea bodies could cease to move were true, there would be a disanalogy – after all, one who is awakes from sleep would not do so if he were not continually perceiving and sensing externals.
One final example of a fundamental disagreement between Locke and Leibniz may be attributable to Leibniz’s seeming stress on the importance of theodicy. Leibniz disdained what he perceived to be a logical extension of Locke’s philosophy, viz. “that simple substances influence one another, replacing influence by mere correlation.” Leibniz thought Locke did not sufficiently address the reason men perceive secondary qualities, for the seeming arbitrariness was obviously at odds with Leibniz’s philosophical belief that the universe is made up of simple substances in perfect harmony with one another according to the eternal, purposeful will of God.