A debate rages in philosophy about whether intuitions can help us know the truth.

The intuitions in question are psychological states that arise in response to real or hypothetical examples. A classic example (mentioned on the recent intuitions show): imagine Jewish people are in your basement and a Nazi is at your door in 1942. Is it right to lie to the Nazi? Intuition in this case favors lying.

But is this intuition really showing us the truth? Do intuitions tell the truth in general?

Three positions have emerged.

Position 1: Yes…intuitions show truth! Skeptics be damned—when one has an intuition, one has an insight. George Bealer prominently advocates this view. Intuitions are “intellectual seemings,” a priori appearances of basic truths to the intellect.

Position 2: No way…intuitions are just subjective burps! If we’re trying to figure out what reality is like, what good is intuition? Intuition is just an internal subjective response. Stephen Stich often represents this camp. And we’ve also seen some of this skepticism from Philosophy Talk’s own Director of Research, Laura Maguire.

Position 3: Well…intuitions teach us about concepts. While intuitions might not tell us about a reality “out there,” they do teach us about our own concepts—internal representational structures. We often use concepts like RIGHT, WRONG, JUSTICE, KNOWLEDGE, etc. As Alvin Goldman put it on the show, intuitions can give us insight into “basic, pervasive concepts.”

Must we choose one of these three? I wish to argue that all of these positions fail to characterize what’s most important about intuitions.

An important prerequisite to any interesting knowledge, I claim, is having a sense of what questions are important. And here the philosophical and scientific activity of doing thought experiments and getting intuitions is most useful. As Daniel Dennett puts it, “Philosophy—in every field of inquiry—is what you have to do until you figure out what questions you should have been asking in the first place” (Intuition Pumps, p. 20). And figuring out what questions to ask is often the precursor to doing science. This leads to our fourth position.

Position 4: Intuitions tell us when we need to ask more questions—and what to ask about. Intuitions about a given subject matter, from morality all the way to physics, tell us, effectively: “Look here! You may think you’ve gotten everything figured out on this subject, but really you’ve got more work to do before you arrive at knowledge.” Intuitions, properly understood, shake us from intellectual complacency and motivate the more exact questions we should ask.

Position 4 is the view I take, inspired very much by Dennett. An MA student of mine, Ben Freed, is also developing a version of it. Let’s illustrate it with a classic thought experiment from science.

Galileo famously argued against Aristotle with a thought experiment about falling objects. The Aristotelian view (still popular in Galileo’s day) was that heavier objects fall faster than lighter objects. So Galileo asked: what should happen according to Aristotle’s theory if we tie a heavier object to a lighter object and drop the combined object? Aristotle’s theory seems to make inconsistent predictions. On the one hand, the light object (on Aristotle’s theory) should put a drag on the heavier object, since the lighter is slower, which means that the combined object should fall slower than the heavy object alone. On the other hand, the combined object is heavier than the heavy object by itself, so (on Aristotle’s theory) the combined object should fall faster than the heavy object.

Fall faster and fall slower? Yikes!

Is this not a straightforward reductio ad absurdum of Aristotle’s theory of fall? Well, no. If we look carefully, we see that this thought experiment doesn’t pin a simple contradiction on Aristotle. But it does elicit an intuition that something isn’t right, no matter which way you try to fix the view. And this latter intuition guides us to the questions we should ask, exactly as Position 4 predicts.

First, let’s see why the thought experiment doesn’t pin a simple contradiction on Aristotle. Aristotle could say something like this: “Well, if the objects are properly connected, the combined object will fall faster than the heavy object by itself. If the objects are not properly connected, the combined will fall more slowly due to the drag of the lighter.” Technically, the supposed contradiction is escaped by this reply.

But here we have another strong intuition: namely, the reply is bullshit! …something (to use Aristotle’s own words) only a philosopher would say for the sake of remaining consistent.

Our intuition that the Aristotelian reply is bullshit is not knowledge. Rather—properly taken—it shakes us from our prior complacency. Given our antecedent views about the physical world, it was easy to accept Aristotle’s theory. But the intuition we have in response to Galileo’s thought experiment tells us that we need to do more research. That’s the key. In particular, we need data from timing falling objects.

Not until we do further empirical research do we actually arrive at the knowledge that falling acceleration in a vacuum is the same for all objects regardless of mass. But—and this is the crux of Position 4—doing the thought experiments and having the Galilean intuitions were crucial steps on the road to that knowledge.

In sum, without thought experiments, we are sometimes not even able to have the right thoughts that would lead to knowledge. So thought experimental intuitions don’t yield knowledge straightaway. They are rather, in some cases, conditions for the possibility of acquiring knowledge.

How does this view apply moral cases, like the Nazi at the door example? The key point will still be that intuitions point the way to the right questions, even if they don’t give answers. Our intuition in response to that example raises the questions, “Are there exceptions to the general wrongness of lying? And if so, what’s the principle behind the exceptions?” To date, it’s not clear that these questions have been answered satisfactorily. Moral philosophy is hard. But we should certainly thank our intuitions for raising them.  Further, I would argue that the intuitions here make us feel the relevance of the psychological consequences of lying and being lied to, thereby joining moral and psychological research programs. That, at least, is some progress.