>>12603629Teleology means the explanation derived from aim or purpose instead of the origin or cause.
Natural selection is not directed or orchestrated, traits like depression don't evolve for a reason, so there is no why.
However they stay in the gene pool if:
- they do not manifest at a stage where the reproduction is hindered (eg. male pattern baldness)
- they provide some benefit
As some have postulated there is a hypotesys of apoptosis which falls under the second, the first option is also valid or could be if in the recent history depression would not affect the survival of the individual or it's expression was not as noticeable, i.e muh modern evil world.
