Neil DeGrasse Tyson's Epistemology

One often finds epistemological questions that can be best answered with common sense. In other words, it seems common sense to most people that it is sight which tells us that, say, the sun is shining, that it is day rather than night, that we are inside instead of out, and so on. In Death by Black Hole, Neil DeGrasse Tyson generally acknowledges such experience as giving us a type of knowledge about the world. But for him, it is not just our senses which give us most of our knowledge, but our senses in conjunction with advanced scientific hardware and mathematics that tells us what the world is really like.

Seen this way, Tyson’s epistemology is essentially classical empiricism updated to acknowledge those mechanisms which expand our senses and clarify what our senses see vaguely (or not at all). One thinks of bacteria, sound waves, the light spectrum, and so on. However, even without denying that microscopes and telescopes give us knowledge about the world around us not accessible by our senses, one might wonder if Tyson has left something vital out of the equation. That is, the epistemological statement that knowledge is gained only by the senses is self-defeating, since that very claim to truth is not known by the senses. Tyson fails to mention the role of reason in answering how we know what we know, but his admission that we use mathematics presupposes reason, given the nature of mathematics. Historically those who believe mathematics gives us truth about the world have been divided, and this is where Tyson’s epistemology stands or falls. A look at the nature of mathematics and reason will help clarify Tyson’s epistemological claims.

Attacks against the empiricist position have traditionally turned on the claim that our senses are misleading and do not give us an accurate representation of what the world is really like. Examples such as Plato’s Allegory of the Cave and Descartes ball of wax illuminate this position. The claim is that our senses tell us something about the world, but that they are mistaken quite often. We can think of Berkeley’s example of a person who sticks a warm hand and a cold hand into the same tub of water. The person will judge the temperature of the water in two different ways, but surely the water is not actually two different temperatures. Likewise, Tyson explains that the history of science is full of examples of reality being quite different than our observation of it. Our errors about the size, shape and rotation of Earth, its place in the universe, and the movement of stars and other celestial bodies have all been based on empirical observations (for example Tyson, chapter 3).

This is the reason Tyson has amended his epistemology to include “the direct application of sense-transcendent mathematics and hardware” (Tyson, 29). The hardware, then, is what tells us the chemical makeup of substances, the empirically verifiable nature of the universe and so on. The really interesting part of his claim is the part about “sense-transcendent mathematics.” How do we know mathematics gives us truth about the world? The answer is far from obvious, and is of course hotly debated by philosophers and mathematicians. But for an empiricist such as David Hume, mathematics gives us truth, but that truth is vacuous. It is only true by definition because we make up the rules. For him, there was no transcendent or abstract realm where mathematical truths existed, and therefore math gave us no real truth about the world.

While Tyson does not directly address the ontology of numbers and mathematical concepts, his work as an astrophysicist is a testimony to the usefulness of mathematics, and he does, in fact, include them in his epistemology. Without entering into the highly technical discussion of the philosophy of mathematics, it is sufficient to note that if one holds that mathematics gives us truth about the universe, what is really being affirmed is the usefulness and applicability of human reason. For example, if one understands the concepts of “2”, “4”, “addition”, and “equals”, the sum of 2 and 2 being 4 is unavoidable. Likewise, our ability to understand mathematical concepts from geometry, like the sum of the interior angles always being 180 degrees is not discovered by measuring every triangle in existence, but only by our use of reason. In this way, our knowledge of triangles is not from our senses, but from our reason.

For one to use mathematics on the level of an astrophysicist one must have a certain level of faith in the reliability of numbers. The launch of a space-shuttle is planned using mathematics that are known here on the earth and elsewhere in the universe. Physical constants such as gravity and the speed of light, as well as the laws of conservation can all be expressed mathematically, but what this shows is that, regardless of the ontological status of mathematical concepts, we use our reason to understand mathematics. That is just the type of thing mathematics is. And this is ultimately what Tyson has failed to include in his claim about how we know what we know.

The presupposition of human reason is made, but the implicitness of the claim is rather suspicious. To include “sense-transcendent mathematics” without including reason would be like including the sense-expanding hardware without including the senses. Indeed, microscopes work, but they are only useful to one with good vision. Likewise, mathematics work, but only to one with the ability to use reason. So what is the problem with the explicit omission of reason if it is understood?

When one accepts human reason as an avenue for knowledge, as one must to allow for our understanding of mathematics, one must also allow for truths known a priori. In other words, there are things we can know without the need of experience at all. They are know prior to our experiences. We can make claims about triangles we have never seen. We can know things about parts of the universe we have never visited. These are truths known a priori. Even if a claim arises from some previous experience, it can be known without a specific experience. For example, what we know about one star might arise from what we know about other stars, but it need not be from our experience of that specific star. In this way, the definition of knowledge changes from simply those things we know from science and mathematics to something like justified true belief. In other words, the claim that we can only know things available to our senses with the help of hardware and mathematics remains self-defeating because the claim itself cannot be verified by its own standards of senses, hardware or mathematics.

We can supply numerous other examples of truth claims for which we do not have empirical data, but which are nonetheless reasonable to hold. It is important for any epistemology to admit that there are things we can know that are outside of what Tyson has given us. The important distinction might be that, for things we know scientifically we may have more rigid standards. Because science is a methodology, such methodological constraints may be necessary, but even the acceptance of mathematics betrays the need for reason and truth known a priori. Tyson is not always clear about what we can know, strictly speaking, since he says that “after the laws of physics, everything else is opinion” (Tyson, 37). Of course Tyson believes we can and do have truth; it is likely that he is being clear to hedge his bets in light of the great number of claims that have been shown to be false throughout the history of science. But nevertheless, human reason and its use in our apprehension of truth in the universe cannot logically or consistently be denied, as Tyson himself implicitly affirms, omissions notwithstanding.