Interestingly, some people have argued that they did lack our depth. [1] Personally I don't think it's relevant to this discussion. Saying that consciousness i

Interestingly, some people have argued that they did lack our depth. [1] Personally I don't think it's relevant to this discussion. Saying that consciousness is more complex than "you either have it or you don't" seems like a trivial observation. Peter Singer argues [2] that "the fundamental interest that entitles a being to equal consideration is the capacity for suffering and/or enjoyment or happiness" (and that this applies to any being, human or not). I think that this is a much more interesting approach. Yes, this makes things more complex ("where do you draw the line") but it also seems more honest. 1: https://en.wikipedia.org/wiki/Bicameralism_(psychology) https://en.wikipedia.org/wiki/Bicameralism_(psychology) 2: https://en.wikipedia.org/wiki/Peter_Singer#Applied_ethics https://en.wikipedia.org/wiki/Peter_Singer#Applied_ethics