Life is exogenous to the universe. That gives life it's meaning-to define what it is through it's impact on the universe. This is because the universe is in average empty and lifeless. The inanimate universe vastly outweighs the animate. Life could not ever overcome the average emptiness of the universe. But still it must try. It must try because if it ceases it becomes the inanimate. Life is that exogenous influence on the universe not attributable to any other physical or chemical process. If you simply cannot explain it then it may be life.

Brain evolution over time is definitely dependent upon physics/chemistry - but it's also dependent on conditions at higher levels of abstraction. We know neurons change their associations every day based on many factors at the conscious and subconscious levels (observations/thoughts).