epiphenomenalism

epiphenomenalism: The doctrine holding that mental activities are simply epiphenomena of the neural processes of the brain.

But the best analogy I ever heard for this idea, possibly from Jung, is this: epiphenomalism considers thinking to be like the steam that rises above a plate of hot spaghetti. We don't consider the steam to be an integral part of the spaghetti. We don't like spaghetti because we like the steam. (Yes, we usually like our spaghetti hot, but again, the steam is just the epiphenomenon of the heat.)

Thinking just happens to be one of those neat things that occurred accidentally as our brains -- whose purpose is simply to perform those autonomic and reflexive actions that keep us alive -- developed and evolved.

The term "epiphenomenalism" is used to describe a view in philosophy of mind -- the view that mental states are epiphenomena of physical states.

Epiphenomenalists believe that mental phenomena (such as sensory experiences, or beliefs) are caused by physical phenomena (brain states) but can't have any effect on the world. I.e., mental phenomena are causally-inert "by-products" of physical occurrences.

In general, accusing a philosopher of making mental states epiphenomenal is a serious criticism -- for it would be a surprising view which held that our desires and intentions don't make us do things, or that my pain didn't make me yelp. There are philosophers who embrace this conclusion, though. (Two quickie examples: functionalists, for the most part, believe that qualia are epiphenomenal. Donald Davidson's anomalous monism may lead to epiphenomenalist consequences.)

Notice that saying mental states are epiphenomenal is different from saying there aren't any mental states (as, for example, eliminative materialists do). It's also different from Cartesian interactionist dualism (epiphenomenalism can be dualist, but the interaction isn't two-way -- physical causes mental, but mental never causes anything).