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Philosophy As Proto-Psychology

Philosophers are often trying to understand their intuitions about thought experiments. Traditionally, philosophers do this via introspection. But these days, some philosophers do it more scientifically: they survey people’s’ intuitions and use quantitative arguments for theories about the intuitions. In this post, I want to point out that one of philosophers’ traditional methods might be a kind of proto-psychology. And if that is right, you might wonder, “Is one method better than the other?” By the end of the post, you’ll know of at least one philosopher who argues that the more scientific approach is better.

1.  Intuitions About Vignettes

In Jennifer Nagel’s “Intuitions and Experiments: A Defense of the Case Method in Epistemology”, we read that our judgments about various philosophical cases are intuitive (2012). By ‘intuitive’, Nagel means not explicitly/consciously represented in our reasoning. She follows Stephen Sloman in saying that when reasoning intuitively, we are “conscious only of the result of the computation, not the process.’ (1996). So, for example, “we do not need to possess or apply any explicit theory of knowledge in order to gain the sense that the protagonist of some scenario has or lacks knowledge” (2012, 501).

The idea here is that we have intuitions about all sorts of scenarios — real or imaginary. Further, the idea is that we don’t immediately know why we have these intuitions because we often can’t introspect the details of the intuitive reasoning process. So we come up with post hoc explanations of these intuitions.

2.  Theories Of Our Intuitions

In the case of knowledge, philosophers have spent a great deal of time trying to make explicit our otherwise intuitive theory of knowledge. Legend has it that philosophers’ traditional theory of knowledge went something like this: Someone’s belief that P counts as knowledge only under the following conditions:

  1. P is true.
  2. Someone believes that P.
  3. Someone’s belief that P is justified.

Philosophers sometimes call it the Tripartite Theory Analysis of Knowledge. You might also see it referred to as the “JTB theory” — where ‘JTB’ is an acronym for “Justified True Belief”.

3.  Falsification

So how do we test our intuitive theories? More thought experiments! In particular, we imagine scenarios that — if the theory of our past intuitions is right — elicit a particular intuition. So, if we end up having a different intuition about the scenario, then that is supposed to suggest that our theory was wrong somehow.

You might have heard that the JTB theory was famously challenged in the 20th century (Gettier 1963). How? One reconstruction of the story goes like this: Someone came up with a thought experiment, announced their intuition about it, and then explained how their intuition about the vignette falsified the JTB theory.

Precisely what this means for our theory of knowledge is disputed, of course. For instance, even if a philosopher rejects the JTB theory, they often still agree that all three parts of the Tripartite Theory are required for knowledge. So these philosophers don’t think that we should start our theory from scratch, so the speak. Rather, these philosophers think that we should add to the JTB theory. It’s a lot like what scientists do when a theory is challenged: rather than start over, they modify their theory (Popper 1963, 33-39).

4.  Discovery

The philosophers who thought that the JTB theory was falsified were on the hunt for a new theory of their intuitive theory of knowledge. And how did philosophers proceed? Even more thought experiments, intuitions, and theorizing!

For instance, Peter Unger provides a vignette involving a dream, a horse race, and a devious veterinarian (1968). Then Unger intuits that someone in the thought experiment does not have knowledge. From there Unger proceeds to infer what this intuition is supposed to tell us about our intuitive theory of knowledge.

5.  Philosophy as Proto-Psychology

So what’s this got to do with psychology? Well, take a look at one paradigm in social psychology. First, psychologists give people thought experiments like the following (Paxton, Ungar, and Greene 2012):

John is the captain of a military submarine traveling underneath a large iceberg. An onboard explosion has caused the vessel to lose most of its oxygen supply and has injured a crewman who is quickly losing blood. The injured crewman is going to die from his wounds no matter what happens. The remaining oxygen is not sufficient for the entire crew to make it to the surface. The only way to save the other crew members is for John to shoot dead the injured crewman so that there will be just enough oxygen for the rest of the crew to survive.

Second, psychologists get peoples’ intuitions. They ask people about whether John can kill the injured crewman to save the rest of the crew. They also manipulate peoples’ psychology to see how their intuitions change. For example, they might measure the intuitions of two slightly different versions of the thought experiment to see whether and how intuitions about the thought experiment change.

Third, psychologists theorize about the intuitions. They quantify the impact of some change to a thought experiment on participants’ intuitions. And they use this quantitative information to inform their theory about how people form their intuitions.

Sounds pretty similar to what our philosophers were doing, right? I mean, sure: philosophers didn’t survey other people’s intuitions. They typically surveyed their own intuitions. And philosophers didn’t conduct statistical analysis. But the other similarities between the philosophers’ and the psychologists’ method are striking. And that is at least some reason to think that philosophy’s use of thought experiments is a sort of proto-psychology. Or, in the words of Kaija Mortensen and Jennifer Nagel, it is a sort of “armchair-friendly experimental [psychology]” (2014).

6.  Rebuttal

The front cover of Philosophy In Its Proper BoundsIf you’re interested in the claims here, then you’ll probably be interested in the claims of a new book: Philosophy Within Its Proper Bounds (2017). In the book Machery evaluates philosophy’s method of theorizing about their intuitions about thought experiments (otherwise known as “the method of cases”). Machery distinguishes philosophers’ method from psychologists’ method. And then Machery argues that philosophers’ method is inferior to the more scientific method — which Machery dubs “The Method of Cases 2.0”. It’s an interesting and important read for anyone who cares about philosophy.

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Nick Byrd

Nick is a cognitive scientist at Florida State University studying reasoning, wellbeing, and willpower. Check out his blog at