The brain is a mystery—it has been—and still will be. Not that we do not know many facts about it. The facts we know have indeed greatly multiplied i… - Charles Scott Sherrington

[M]an's life of all lives is the most completely and fully bound to earth because life's experience, wholly earthly, is in man's case the most complete and full. […] Man is the most, not the least, earthly of all creatures.

The 'motion' of an energy-system is its 'behaviour'. Various types of organization of system produce on that basis various types of behaviour. A grey rock, said Ruskin, is a good sitter. That is one type of behaviour. A darting dragon-fly is another type of behaviour. We call the one alive, the other not. But both are fundamentally balances of give and take of motion with their surround. To make 'life' a distinction between them is at root to treat them both artificially.

And the pursuit whose quest is Nature's understanding, has this among its rewards, that as it progresses its truth is testable. Truth is a 'value'. The quest itself is therefore in a measure its own satisfaction. We receive the lesson that our advance to knowledge is of asymptotic type, even as continually approaching so continually without arrival. The satisfaction shall therefore be eternal.