Causal Closure, Synaptic Transmission and Emergent Mental Properties

The causal argument for physicalism about the mind has received a lot of attention. In particular, the literature has focused on the main premise of the argument, namely the causal closure principle (CC). In this article, I present and discuss the so-called argument from physiology, that is widely regarded as the most convincing line of reasoning in favour of CC. When it comes to providing empirical grounds for the argument from physiology, the most promising move the physicalist can opt for is to focus on the mechanisms of synaptic transmission. Here, I argue that the argument from physiology can provide support for CC only if evidence concerning synaptic transmission is combined with a non-innocent assumption about the internal causal organisation of the nervous system. I contend that this assumption should be vindicated. Unfortunately, this does not seem to be possible at the moment.