The Nature of Consciousness

Piero Scaruffi

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These are excerpts and elaborations from my book "The Nature of Consciousness"

Brains are for Traveling and Chatting

What are brains for? Why a rock or a plant can be what it is without a brain, while an animal cannot exist without a brain? What is the unique feature that a brain enables?

One property of living beings is striking. Plants, which do not move, do not have brains. They too grow and they too need to coordinate their growth, but they don't seem to need a brain to do so. Mammals and birds appear to have the most sophisticated ability to move. Mammals and birds also have the most sophisticated brains. The brains of snakes, frogs and fish appear to be simpler, and it turns out that these creatures do not move in as creative a way as mammals and birds. Invertebrates have even simpler brains and their movements are even more basic. Birds and mammals can move very long distances, over huge territories, dealing with a broad spectrum of ecological changes, even crossing oceans and continents, and they can move in a virtually endless variety of ways. Other animals seem to be more limited both in distance and in the degrees of freedom of their movements.

Another property of living beings stands out.

The biggest brain (about 10 kg) belongs to the sperm whale. The record for brain size compared with body mass belongs to the squirrel monkey (5% of the body weight, versus 2% for humans). Some birds too have a higher "brain percentage" than ours (the sparrow is a close second to the squirrel monkey).  Two rules seem to tell something about the reasons for larger brains: 1. Bodies of warm-blooded animals consume ten times more energy so brains can be ten times bigger. 2. Species that live in large social groups have the largest brains (the squirrel monkey lives in bands of hundreds of individuals).

That said, let us not forget that the longest living beings on this planet have no brain: trees and bacteria.


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