Finding Biological and Psychological Analogues: Where Are Conscious Brains And How Can We Identify Them?

Conscious brains have only been observed in the earth’s biosphere. Conscious beings may exist on other planets but we do not have evidence for that.

There are two additional facts that constrain the set of potential candidates:

First, all the conscious entities we know have neurons, which are highly specialized signaling cells. Neurons are not a single “species” of cell, but a very widely varying class of animal cells.

Neurons are very expensive and thirsty cells, and therefore require major metabolic support, and possibly a sleep period during which metabolic toxins can be disposed of.

Although there is a great deal of speculation about machine consciousness, there is no direct evidence for consciousness outside of living animals.

Second, neurons that give rise to conscious experiences appear to be interconnected in very specific but flexible ways, either in the cortico-thalamic system in mammals, or possibly in the paleocortex of pre-mammals, or, potentially in the “pallium” (aka “cortex”) of birds, reptiles, amphibians, and perhaps amniotes.

Regarding invertebrate species: It is possible that the connectivity among masses of neurons is the key, and that the specific distribution of those neurons is not.

That might open the door to cephalopods.