Causal Parity and Externalisms: Extensions in Life and Mind

This paper questions the form and prospects of "extended theories" which have been simultaneously and independently advocated both in the philosophy of mind and in the philosophy of biology. It focuses on Extend Mind Theory (EMT) and Developmental Systems Theory (DST). It shows first that the two theories vindicate a parallel extension of received views, the former concerning extending cognition beyond the brain, the latter concerned with extending evolution and development beyond the genes. It also shows that both arguments rely on the demonstration of causal parities, which have been undermined by the classical received view. Then I question whether the argument that there is an illegitimate inference from parities or coupling to constitution claims, which has been objected by Adams and Aizawa in The bounds of cognition, (2008) to EMT, also holds against DST. To this aim, I consider two defenses against DST that are parallel to two defenses against EMT, one about intrinsic content, the other about the difference between what's in principle possible and what happens in practice. I conclude by claiming that the weaknesses and strengths of both theories are different regarding these two kinds of objections.