I would argue it's because they don't have a spirit, and the spirit is where intelligence and memory happen.
The brain merely conects the spirit to the body. When there is brain damage, or body damage, the spirit cannot control or work through that part of the brain or body.
I tend to separate raw intelligence and consciousness—not because I believe they are separate, but I just don't know how to quantify consciousness.
We know a few things about critical thinking, technical intelligence, and IQ, even within these parameters, something seems to be missing in these models that we don't fully understand.
Still, it's astounding how much can be achieved with just matrix multiplications.
