As a psychiatrist, I’m intrigued by the mind and brain.  But what exactly is the relationship between these entities – mind and brain – terms that are often used interchangeably.  My philospher-husband has this to say:

Suppose you hit your thumb with a hammer.  You’ll certainly feel a painful sensation in your thumb.  You’ll most likely exhibit certain pain behaviors, such as wincing and holding your thumb.  Do you believe that the painful sensation causes these pain behaviors?  I’d bet that you would.  But if you believe this, then you face a philosophical question.  How can something in the mental realm, such as a painful sensation, cause something in the physical realm, such as pain behavior?

You might think, “Well, mental events just cause behavior.  I don’t know how they do this, but I’m sure science can explain it.”

This way of thinking may be correct, and there are a number of philosophers who’d agree with you.  But this way of thinking assumes that mental events can be understood scientifically, and there are many philosophers who’d deny this.  These philosophers believe that mental events aren’t physical, and hence can’t be understood by science.

(Remember that when I say that mental events are or aren’t physical, I mean that they can or can’t be understood with physical vocabulary – the terms used in the physical sciences, such as chemistry, neurophysiology, and biology.  See here for further comments on what it means to say that mental events are or aren’t physical.)

Philosophers who believe that mental events aren’t physical (sometimes called “anti-physicalists”), wonder how something that isn’t physical can cause something that is physical.  This puzzle is known as The Mind-Body Problem.  The Mind-Body Problem can be traced back in history to at least the 17th century, when the philosopher Rene Descartes, now known as one of the most famous anti-physicalists, was challenged by one of his students to answer it.

Descartes believed that your mental events aren’t part of the physical world, but rather belong to an immaterial soul, something that neither takes up space nor is located in space.  Descartes also believed that your soul and your body causally interact.

Princess Elisabeth of Bohemia, one of Descartes’s brightest students, asked Descartes to explain how a body could be moved by an immaterial soul, something that isn’t spatial, if it can only be moved by contact.  Descartes’s answer (in a nutshell):  It just does.  There is no need for an explanation.

Is Descartes’s answer satisfactory?  Many philosophers think not.  But if it isn’t, then what should we say in response to The Mind-Body Problem?  Here are 3 options:

1. Deny the commonsense idea that mental events cause anything.  This means that your painful sensation in your thumb didn’t cause you to wince or hold your thumb.
2. Deny the underlying assumption, that mental events aren’t physical, and conclude that the Mind-Body problem is only a pseudo problem.  (In a later post, I’ll discuss this assumption.)
3. Acknowledge that the Mind-Body Problem is a deep philosophical difficulty, one that we may never solve.

What’s your view?  Is your painful sensation physical?  If not, then does it seem mysterious how something non-physical could cause physical, bodily behavior?

The painting above is Philosopher in Meditation by Rembrandt, 1632.