These questions are traditionally associated with a particular form of inquiry. Roughly:
- Think very hard about different states of the world in which X is clearly present.
- Detect some property (or set of properties) P shared by all such states.
- Propose P as necessary and sufficient for X.
- Submit your proposal to other philosophers for rigorous cross-examination.
I say 'theoretically' because we are entitled to ask why. What theory of inquiry motivates the view that we can learn substantive truths about the world just by reflecting on the content of own minds?
One possible reply is this: We don't need no stinking theory of inquiry. We just need to point to a heap of solid results produced thereby. Right. Well, there's the rub.
Plato, who raised this form of inquiry to high art, seemed to recognize that this question requires an answer. In struggling with it, he was led to one that is as beautiful as it is absurd: Our souls contain every truth worth knowing, but we forget them during the trauma of birth. On Plato's view, what we call learning about the world is really a process of recollection. This is his theory of anamnesis, which leads Plato to endorse an ancient myth of reincarnation.
Plato's basic answer persisted in one form or another as the doctrine of innate knowledge. Two thousand years later we find a fellow traveler, René Descartes, smack in the middle of the scientific revolution, self-consciously defending the same basic method in his Meditations on First Philosophy. Descartes famously argued that the Creator outfitted our intellect with innate indubitable knowledge of the kind of world we live in as well as reliable resources for learning all about it.
Usually we characterize the rationalist commitment to innatism by reference to the view that genuine knowledge is incorrigible, i.e., true beyond all possible doubt. Rationalists like Plato and Descartes believed that only the exercise of pure reason could produce such truths. But empiricists like Aristotle and Hume accepted the incorrigibility of genuine knowledge as well. What they hated was the conclusion that to know we know anything about this world we must presuppose a completely different one.
So a commitment to innatism has two main sources. One is the view that empiricism is too impoverished a framework to explain the possibility of human knowledge. The other is that it justifies the traditional method of philosophical inquiry.
Maybe now I will say this? Our experience with science has taught us that empiricism is right and innatism is wrong. So it's high time we exchanged armchair philosophical methods for more enlightened naturalistic ones. Well, there are plenty of philosophers today who do say this. I tilt that way. But it is too easy. Let's see why.
First, let's be clear that empiricism has, for the most part, won. But that is not because classical empiricists succeeded in showing that the ultimate foundation of infallible knowledge is experience. It is because science, using a fundamentally empirical method, has amassed a magnificent mountain of knowledge in the absence of any such assurances. By brute force, the success of science has ushered in an age of fallibilism, which is the idea that we can come to know X through methods that do not guarantee the truth of X.
Epistemologically speaking, this is just a whole different world. Back in the day, empiricists and rationalists disagreed on the ultimate foundation of knowledge, but they totally agreed that, whatever its source, the method for producing knowledge had to assure certainty. It just couldn't be any other way. But they were all wrong. Scientific knowledge is not deduced from first principles. It originates in guesses, hypotheses that attempt to account for why we observe the world behaving as it does. Hypotheses that survive extended, merciless testing get promoted to theories and may ultimately earn the status of knowledge. But they never get tenure. All scientific theories remain subject to performance review and none rise completely above their uncertain provenance.
Second, innatism persists within science itself. Rationalists were actually correct that the mind can not just be a "blank slate" at birth. In order to be capable of gaining knowledge about the world, it must begin with some kind of basic structure. Scientists differ with respect to the content and plasticity of these presuppositions, but nobody represents them as incorrigibly correct. Scientific innatism explains how infant brains can develop into functional adult ones, not how infant brains come into this world containing fundamental truths of the universe.
Third, at various stages of inquiry scientists, too, pose questions of the form "What is X?" and, like philosophers, they must consult their own minds for the answer. But they approach these questions a bit differently than we do.
First, the intuitions they consult are not ordinary intuitions, but those of a specialized research community trained up on a technical vocabulary and specific methods of inquiry.
Second, scientists do not believe that thinking long and hard on a question like "What is a hydrogen bond?" is sufficient to uncover its true nature. They believe that only experiment can reveal that.
Third, this kind of thinking does not occur in a vacuum, but with specific explanatory goals. When Erwin Schrödinger posed the question "What is Life?" he was not taking a holiday from physics to do a little philosophizing. Rather, he was trying to bring living systems within the explanatory purview of his own discipline.
Finally, scientists don't normally try to provide a set of necessary and sufficient conditions for X-hood, and they typically don't get their panties in a bunch over a single striking counterexample to an otherwise useful definition. Scientists work in a manifestly messy world and they have learned how to produce in the face of all manner of uncertainty.
G. Randolph Mayes
Department of Philosophy