Lecture 2: Eyes to See, Brains to Think: The Inevitable Evolution of Intelligence

The striking similarity of the camera eye in the octopus and human (and other vertebrates) is perhaps the classic example of evolutionary convergence.

Slightly less well known is that this solution has been evolved at least seven times, including the extraordinary case in a jellyfish.

Camera eyes are certainly not the only solution, but the principal alternative in the form of the compound eye has evolved independently at least four times, again with a remarkable example where relatives of the star-fish see in the same way as the ancient trilobites. Yet, camera and compound eyes are by no means equivalent, and we can be confident that extra-terrestrial astronomers (if there any) will be observing us through camera eyes. Nor are eyes the only example of repeatedly inventing the same solution.

Across the sensory spectrum - from olfaction to echolocation - convergence is the rule. Even more tantalizing is the evidence for fundamental equivalences of sensory perception and the implication that deeper in the nervous system there is only one mentality. Minds may be not only universal, but also the same.

The consequences of this possibility are far from abstract. New work on the birds, especially the crows, indicates that the convergences in such matters as social play, song and tool-making all point to the emergence of sentience as an evolutionary inevitability. Such sentience, even in animals, opens the doors to the discernment of abstract possibilities, and so the first step to discovering that the world around us is not necessarily all that it seems.

This lecture has been recorded on MP3: