Mark asked:

I don’t understand why philosophers sometimes call the mind, the soul. Just like the heart beat is a function or characteristic of the physical heart is not the mind simply a function or characteristic of the physical brain, and once the brain ceases to exist so does the mind?

Answer by Julian Plumley

The Greek word for soul, psuche, comes from the verb ‘to blow’ and literally means something like the ‘breath of life’. It referred to that which animates the body and makes us alive. Simply put, without soul, we would be just so much meat. Soul included everything we would today mean by ‘mind’ . So, for example, Plato’s theory included a rational, thinking part (closest to what we mean by ‘mind’) an emotional part and an appetitive, instinctive part. His theory doubles as psychology and as metaphysics. He uses it to explain our inner conflicts when we make decisions. And he takes the soul to be immaterial and eternal, and separable from the body.

This set the pattern for many different theories of soul put forward at different times. Not all of these have assumed that the soul is immaterial – Aristotle did not think a soul could existed in isolation, but that it was a substance that essentially animated a person’s body. But these theories generally share two assumptions: i. that what they are trying to explain is what makes us a living thing; ii. that the soul is the ground of our personal identity – what makes us an individual subject with its own viewpoint, rather than an object.

Religious groups have adapted the idea of soul to fit in with their belief systems. For example, some Christian theologians fit the soul into a tripartite theory of spirit (pneuma), soul and body. The soul’s functions are usually given as reason (mind), volition (will) and emotion. In addition, it is claimed that the soul (and perhaps also the body) may survive death and be resurrected.

In more recent times, life has been studied scientifically. The old assumptions are no longer the starting point. Firstly, in science there is no one particular thing that makes us alive. We are alive because of all the chemical and biological processes that go on in our bodies. Mind may be distinguished from body and studied under the various cognitive sciences. There are competing theories as to what a mind may be, perhaps a neural net, or maybe more like a computer program. But the methodological assumption of these sciences is that mind is generated by the physical brain, just as a heartbeat is the result of a working heart. This is backed up by observations using various types of scanning technologies that show our neurons working as we think. A consequence is that the mind could not survive the death of the brain.

Secondly, science does not deal with subjects or substances. The scientific assumption is that reality is objective (Searle). As Thomas Nagel pointed out, the methodology of science calls for objectivity, which abstracts away from understanding the subjective standpoint. And if you do turn out to be a computer program, then you are an item of information, not a person: one is a universal, the other is a particular – you cannot be both.

For both these reasons, science has no use for ‘soul’ in its vocabulary. Soul is an answer to questions that science does not ask. So a modern philosopher who talks about ‘soul’ is either: i. using the term in its pre-scientific way (perhaps talking about a historical viewpoint); ii. discussing religious concepts; or iii. dealing with metaphysical problems that are not scientific (although Nagel wonders whether science could be adapted to include them).

As a philosopher, the remaining question is whether you are satisfied with the questions and answers that science can provide. Leaving religion to one side, the question is whether you want to take metaphysics seriously. Science eliminates the metaphysical questions of subjectivity and personal identity, agency and free will. If you can live without these, then you have no need of the concept of the soul.

P.S. You might also like to read a previous ask-a-philosopher answer here: