A philosophical tradition going back to Descartes assumed that human beings have an indubitable consciousness of their own minds but that knowledge of other minds was at best inferred. What they failed to see was that the consciousness, the felt experience that could not be doubted, was not the same as introspection. William James, as mentioned in Chapter 4, was guilty of this conflation. Introspection is enabled by mental concepts used in ascribing mental states to others. Put simply, introspection is self-ascription; one cannot introspect without linguistic concepts of mind. As Montgomery (2005, p. 120) pointed out in regard to children’s acquisition of theory of mind, “introspective knowledge [plays a much smaller role] in mental concept formation than is sometimes claimed.” Montgomery’s concern has been ignored by those influenced by Simulation Theory.

In the first part of the chapter, I review evidence showing that the same centers controlling laughter are also involved in generating the affective aspect accompanying laughter, in line with pragmatists’ theories of emotion. Subsequently, I discuss new data showing that these centers can be activated by the passive observation of others’ laughter, hence a “mirror mechanism” for laughter. Inspired by James’ assumption that “the whole function of thinking is but one step in the production of habits of action”, I argue that this mechanism boosts two distinct sets of “habits of actions”, at different timescales. First, laughter mirroring underpins behavioral phenomena such as facial mimicry and laughter contagion that, in turn, play a crucial social function in boosting social bonding. Second, the consequences of laughter mirroring impact on social customs, traditions, and habits which, in turn, impacts on individual brains and emotions – in line with theories on the social genesis of self, advanced by all classic pragmatists.

On one interpretation, Jaspers’ discussion of imaginative understanding explains how we know causal relations between psychological states. Cognitive neuroscience models of delusions typically aim at characterizing the organic disturbance that underlies the ‘primary delusion’; then, it’s assumed, mentalistic causation takes over and generates the other symptoms. No account is given of the biological underpinning of psychological causation. Imaginative understanding is not well-described by ‘simulation’ models. Simulation theory is predictive and does not attempt to find causation. Imagination here is best understood as correlative with the idea of a psychological process; imaginative understanding of psychological processes drives our ordinary conception of mental causation. We know roughly what a psychological process is and what a biological process is.But there seems to be no presumption we can map one onto the other. I review the options here and something of their implications for how we think about mind and brain in psychiatry.