Mind and body · Quiz question 24/35
Penfield's Brain Stimulation and the Identity Theory
Zap a spot in the brain and a childhood memory comes flooding back. Does that mean the mind is physical brain events? Penfield's experiments and mind–brain identity theory.
During surgery, doctors electrically stimulate a spot in a patient's brain — and the patient vividly relives a childhood scene, feelings and all.
Everything that happens in the mind is made of physical brain events like this.
Canadian neurosurgeon Wilder Penfield reported that when he electrically stimulated the temporal lobes of awake epilepsy patients during surgery, some vividly experienced past scenes or sounds; he summarized this with Perot in Brain in 1963. In philosophy, U. T. Place and J. J. C. Smart proposed in the late 1950s that conscious states like sensations are identical to brain processes — the "mind–brain identity theory."
Stimulating the brain to produce experiences is strong evidence that mind and brain are tightly linked. If you agreed, you're a physicalist who thinks that link is identity. Smart argued that just as "lightning is electrical discharge" was a scientific discovery, "pain is a certain brain state" could be discovered too.
A few cautions. First, correlation isn't identity — dualists also agree the brain affects the mind (even Descartes's interactionist dualism does). Second, Penfield himself leaned toward the view that the mind can't be fully reduced to the brain in his late book The Mystery of the Mind (1975). Third, Hilary Putnam's "multiple realizability" argument — the same mental state could be realized by very different brains in an octopus and a human — challenged simple identity theory and led to functionalism.
Mental events are physical brain events, full stop.
Key names: Place, Smart, Paul ChurchlandThe mind is the functional role the brain plays — it could be realized in other materials too.
Key names: Hilary Putnam, Daniel DennettThe brain may be necessary for the mind, but not everything mental is a physical event.
Key names: Descartes, David Chalmers, Thomas Nagel