The evolutionary implausability of outlandish alien cognition

Contemporary arguments for (and against) the extended mind hypothesis (eg. Sprevak 2009) regularly invoke hypothetical aliens with outlandish forms of internal cognition. Sprevak asks us to imagine an alien that stores memories "as a series of ink-marks" (ibid: 9). This is meant to be functionally equivalent to the case where someone 'stores' their memories in an external diary. The point is that, in order to preserve multiple realisability and the Martian intuition, we are forced to accept that both the alien and the diary-user constitute cognitive systems, with the only difference being that the latter extends beyond the biological brain.

Baby Martian?

In another example, this time intended as a reduction ad absurdum of functionalism and the extended mind, Sprevak proposes an alien with an innate, internal cognitive sub-system that calculates the exact date of the Mayan calendar (ibid: 21). Again, his point is that there seems to be no functional difference between this sub-system and the one that he claims to have installed on his office computer¹. Ergo, his extended mind includes this implicit knowledge of the Mayan calendar.

Ignoring for the moment any questions about the extended mind per se, we should question the plausibility of these kinds of aliens. In each case, but especially the second, it seems that our aliens would possess remarkably over-specialised brains. The ink-jet memory system seems cumbersome, and the Mayan calender calculator is an extremely niche-interest device, one that would probably never see any use. In both cases it is difficult to imagine how or why such a cognitive architecture would have evolved.

This doesn't constitute a counter-argument, as regardless of any evolutionary implausibility Sprevak's aliens serve their rhetorical purpose. However it's interesting to note that much of Clark's own use of the extended mind is intended to highlight the way in which human brains off-load these kinds of specialised skills on to the environment (see his 2003), meaning that we are precisely the kind of generalists that these aliens aren't. Perhaps it's important not to get too caught up with outlandish aliens when we consider the extended mind, and return to the much more homely (and relevant!) examples which it was originally intended for.


1. I have a meeting with him in his office tomorrow, so I'll try and check if is true...

References

• Clark, A. 2003. Natural Born Cyborgs. Oxford: OUP.
• Sprevak, M. 2009. "Extended cognition and functionalism." The Journal of Philosophy 106: 503-527. Available at (and references to) http://dl.dropbox.com/u/578710/homepage/Sprevak---Extended%20Cognition.pdf