Overview

John Locke, who we are reading next, famously held that the mind is like “white paper, void of all characters, without any ideas?” and that experience provides all of the ideas in the mind (Locke [1690] 2019, 353L).

Leibniz, writing after Locke, disagreed. The question, as he formulated it, is whether “the soul in itself completely empty like tablets upon which nothing has been written” and “everything inscribed on it comes solely from the senses and experience” or, instead, “the soul contains from the beginning the source of several notions and doctrines, which external objects awaken only on certain occasions” (Leibniz 2019, 464L).

What is innate, according to Leibniz?

What notions and doctrines are innate, according to Leibniz? His best examples concern what he calls “common notions” in mathematics. These come from Euclid’s Elements.

1. Things which equal the same thing also equal one another.
2. If equals are added to equals, then the wholes are equal.
3. If equals are subtracted from equals, then the remainders are equal.
4. Things which coincide with one another equal one another.
5. The whole is greater than the part.

Leibniz is especially impressed by our ability to recognize necessary truths. Experience only gives us experience of some, say, right triangles. How can it show us that the Pythagorean Theorem will be true for all of them?

Leibniz believes that geometry, logic, metaphysics, and morals are all areas of knowledge that concern necessary truths (Leibniz 2019, 464R).

The role of experience

Leibniz agrees that the senses are necessary for the development of our minds. In that sense, all ideas do depend on the senses (Leibniz 2019, 464r). What he denies is that the senses alone are sufficient.

Of course, no one is constantly conscious of every idea that Leibniz, or anyone else, would want to call innate. Leibniz has two things to say about this.

1. “Reflection,” or noticing things about your mind, shows that a great deal is innate: “we are innate in ourselves, so to speak” and “we have within ourselves being, unity, substance, duration, change, action, perception, pleasure, and a thousand other objectsof our intellectual ideas” (Leibniz 2019, 465R). Here the idea is that you are looking inward, much as you would normally look outward: objects of the mind are perceived like external objects are perceived.

2. These “objects” are “always present to our understanding” but “not always perceived consciously.” One of his themes is that there can be perceptions that are not consciously perceived. He cites habits and memories as examples of things in our minds that we are not always conscious of having (Leibniz 2019, 466L).