We do not yet know how consciousness comes to be. What if a functional human consciousness begins to appear when the brain is capable of forming complex and long lasting connections that arise from external stimuli, in our case, our senses?
Imagine the following thought experiment.
1. Imagine a baby being born. Now imagine this baby not possessing a body. But just a free standing brain. (for the sake of simplicity, assume we can keep it alive)
2. If the brain is kept in an isolated environment away from any external stimuli but alive
3. Would it eventually develop an awareness?
If we assume the initial question to be valid. I believe that the baby would not form awareness and that it would have very few connections as opposed to a 2 month old baby.
Then we ask ourselves what allows the human brain to form a more complex consciousness than other mammals if mammalian brains are very similar in structure?
It could be the ability to form complex connections through the culmination of external stimuli and the ability to retain those connections. It could be possible that animals such as dogs and cats are not capable of forming very complex connections within the different sectors of the brain. If so it could either be a physical limitation of their brain or some gene that is not present.
This does not mean animals are not conscious. I believe they do posses a form of awareness but not a very complex one like “functional human consciousness” as defined in an earlier post.
The idea of a spectrum for consciousness begins to present itself.