What if I told you your mind is not like a diamond… it’s more like mousetrap.
Functionalism is a theory in the philosophy of mind that says if we
want to understand the fundamental nature of mental states— like thinking, being angry,
or seeing hot pink—then it helps to think about the nature of mousetraps. So what is a mousetrap?
This is pretty standard. But what about this? Or this? These are very different physical objects,
but they’re all mousetraps. So is this (gross! sorry)… and this too…
though a double mouse guillotine seems a little uncalled for, if you ask me.
Got an afternoon to waste, try going down the mousetrap rabbit hole on the YouTubes, featuring
the “Walk the Plank” mousetrap, the “Rolling Log” mousetrap, and, my favorite, the spinning,
razor-blade, windmill-of-death mousetrap. As you can see, what makes a mousetrap a mousetrap is
not what it’s made of. What makes a mousetrap a mousetrap is what it does. If it functions as
a mousetrap, it is a mousetrap, no matter what it’s made of or how it’s constructed. Even this
could be a mousetrap, if it were to function as one. So some things are w hat they are…
based on their function. But not everything. Take a diamond, for example. What does a diamond do?
It sparkles and shines, draws “oohs” and “aaahhs” from jewelry lovers. But…. cubic zirconia sparkles
and shines and draw “oohs’ and “aaahhs” from jewelry lovers just as well, at least as long
as you don’t have a nosy expert around. But no matter how much cubic zirconia sparkles and shines
or impresses your friends… it’s not a diamond. Because a diamond is not characterized by its
function. It’s not what it does the matters, it’s what it’s made of. If it doesn’t have a
certain molecular structure, it’s…Just. Not. A. Diamond. Functionalism says that the mind is not
like a diamond. It doesn’t matter what it’s made of. The mind…is more like a mousetrap.
As long as it functions like a mind—as long as it does mind-ish stuff—it’s a mind.
Imagine aliens invade our planet, but they don’t have brains—their heads are full a gelatinous goo
with chemical properties our science doesn’t even recognize. They are calculating and planning our
destruction. They want to take over the world and intend to do so.These are all mental states. The
goo in the alien’s heads is doing mind-ish things, so arguably… they have minds. But they don’t have
brains. On this view, any kind of identity theory that says the mind equals the brain,
or that certain mental states equal certain brain states, is just wrong. If wanting is
just a certain kind of brain activity, then these aliens couldn’t want to destroy the earth—because
they don’t have brains! But obviously they do want to destroy the earth. That’s why they’re
pointing their laser cannons at us! In philosophy, we call this basic idea multiple realizability.
Mental states can be realized in different kinds of stuff—not just brains. Sure, our pain is
realized in the firing of neurons but the alien’s pain is realized in the activity of the goo.
Just like trapping is realized by a coiled spring here but realized by a narrow entrance here.
Functionalism helps explain multiple realizability: as long as something
functions in mind-ish ways, then what exactly it’s made of, just doesn’t matter. Maybe you can see
where this is going. Why couldn’t microprocessors realize the functions of a mind? If a machine
were to function just like a human being—if it behaved like it had beliefs and desires,
and handled inputs and outputs in the same way we do, then why deny it has a mind? Or so says
functionalism. In future videos, I hope to talk more about the main challenges to functionalism,
like inverted spectrum, philosophical zombies, and the famous Chinese Room. But now you’re familiar
with the broad outlines of functionalism—perhaps the most popular view in the philosophy of mind.