Dr. Seuss and Philosophy - Jacob M. Held [49]
Non Sense Knowledge
Cogito, ergo sum (“I think, therefore I am”).
—René Descartes
Rationalism shares empiricism’s commitment that our knowledge needs to rest upon a set of foundational beliefs but holds that at least some of our beliefs can be wholly justified by our rational intuitions. That is, we can (and do) know things without relying upon any specific sensory experience. Rationalist claims to knowledge are justified a priori,10 meaning that we can have knowledge before our interaction with any particular empirical evidence. A priori knowledge is usually contrasted with empiricism’s a posteriori knowledge11—knowledge attainable only after interaction with sense-based evidence.
Perhaps the most famous example of a priori reasoning is found later in René Descartes’s consideration of the “evil genius hypothesis.” Recall that given the genius’s power of deceit, we would not be warranted to claim knowledge of even simple things about the world, such as that grass is green or that we have bodies (or that grass and bodies exist at all). In this thought experiment, Descartes recognizes that even if he must doubt that he is embodied and that he knows the color of grass, he is undoubtedly doubting—that he is doubting could not itself be doubted. As doubting is a kind of thinking, and thinking requires a thinker, Descartes proclaims, “Cogito, ergo sum”—I am thinking, therefore I exist.12 He understands that the nature of “thinking” is such that for it to occur, a thinker is required. So, since Descartes is thinking, Descartes must exist—a conclusion that can be reasoned to without relying upon sensory experience. Similarly, when Marco talks about the Thing-A-Ma-Jigger, “A fish that’s so big, if you know what I mean, that he makes a whale look like a tiny sardine!” (Pool), we can know a lot of things even if we’ve never had any experience with a Thing-A-Ma-Jigger, a whale, or a sardine. For instance, we know that if they exist they are the sorts of things that can be measured; we can rank them by relative size and we understand the concept “fish,” so a Thing-A-Ma-Jigger is some sort of creature that lives in an aquatic environment. Other examples of a priori knowledge include our knowledge that 3,977 is not the largest whole number, that all points of a circle are equidistant from the center, and that the Thing-A-Ma-Jigger cannot be simultaneously purple all over and yellow all over.
Another way to draw out the distinction between rationalist and empiricist theories of knowledge is by understanding the difference between “necessary” and “contingent.” Mrs. Umbroso claims that “lungfish breathe.” This is the sort of claim the truth of which is necessary. Given the nature of what it is to be a lungfish, to not be able to breathe is to violate what it is to be a lungfish. Similarly, “all bachelors are unmarried men” and “triangles have three sides” are necessarily true, given the nature of bachelors and triangles.
Suppose instead that Mrs. Umbroso made the claim, “To get to McElligot’s Pool, Eskimo fish travel farther than Tibetan parachuting fish.” The truth of this claim is contingent. Its truth is dependent upon a number of factors: the least of which is that Eskimo fish do in fact travel farther. But its contingent nature runs far deeper than that. Let’s say that the Eskimo fish begin their journey at the southern tip of Baffin Island while the Tibetan parachuting fish begin theirs in a stream in the exact center of Tibet. Other things being equal, the statement’s truth depends on just where McElligot’s Pool is located. Imagine three worlds just like ours except that McElligot’s Pool is in a different