Stoicism.
Self-control, patience, and understanding nature are the means for overcoming destructive emotions. (ones own)
Clear and unbiased thinking (in a word, logic) allows one to understand the reasons for everything.
Strive continuously to improve your ethical and moral well-being while remaining in agreement with nature.
There are some parts of Stoic philosophy that I totally reject, particularly parts of it's earliest version. Needless to say, it has evolved quite a bit since 300 BC. Mostly it stresses virtue, knowledge, and self-control.