Science will continue to progress and discover new things about the human mind, but great thinkers worked out some of its workings a long time ago. There is an ancient philosophy adopted by slaves and emperors, built by the great minds of Greece and Rome, that can help us endure whatever life throws at us. It is stoicism, and certainly has quite a bit to teach us today.
The stoics believed in fate- that the events of our lives are not just out of our control, but decreed by the gods. If people are where they are in the world as a result of fate, a sensible response if for everyone to accept their own standing and carry out their duties dispassionately. The point is to accept what one cannot change and change what one can. I am most interested in the last point; I don't believe in fate, but I do believe that simply reminding oneself to not worry about the uncontrollable is a fantastic way to deal with hardship.
Stoicism appeals to me largely because it can be built upon a foundation of despair. No notion of divine order is really necessary. I can let go of the things I can't control under any conditions. No matter what adversity the world throws at me, I can take comfort in the bare fact that I don't really control the process, so I don't need to be so concerned about it. Nothing is inherently disturbing; we simply interpret events that way, and have some control over that process. Why be upset about being late for class when throwing a fit won't do anything? Even if you can't make that anger dissipate, you can also accept that you are angry for the moment and thus keep it from getting out of control.
Even before I knew what stoicism is, it helped me. Back in middle school and early high school, I had terrible self-regard in math. Looking back, my anxiety seems sort of silly- although I currently get lower grades in math and score in a lower percentile than in high school, I feel pretty good about my mathematical abilities. But my feelings were real enough them, and starting to impair my quality of life. So finally in my junior year, I decided to accept that if I am naturally bad at math, I can't change that, but I could change how hard I worked and get better that way. I ended up with an A in precalculus, the first A in math since eighth grade, and slowly dropped the negativity that had previously burdened me.
The only problem I have with the philosophy is that it can be too passive. Some duties cannot be carried out with passion and rage. Sometimes it is worth fighting an unjust system knowing you will lose. In practice stoicism can lead to supporting an unjust system just because it won't change anytime soon. This is not always a bad option, but stoics will never lead a rebellion. Such a task falls to those with hot blood and passion.
As always, we can't follow any hard and fast rules. But stoicism isn't a bad philosophy to apply to our daily lives. Life will always contain adversity, and it's a good idea to be ready to meet it.