A young man, whom I knew when he was a teenager, reached out to me recently looking for some advice. He has been working in the world for a couple of years, and he told me he was looking to become more and to do more. Upon my inquiry about his convictions, he told me he was attracted to Stoicism. After a few e-mails back and forth, this is the message I put together for him.
For any philosopher, the goal is truth at all costs. I would challenge you to look into the claims of Christianity and Catholicism in particular. I have found Catholicism to be compelling, and I have not been able to deny its truth. My search for truth in philosophy coincides with the truth I have found in that religion, so the resulting worldview is a robust understanding of the world, God, the human person, good, and the meaning of life. Having that foundation helps immensely when making life decisions.
I want to emphasize, though, that my philosophy and religion are not merely utilitarian considerations, let alone an indulgence of my predilections or preferences; truth is its own reward and ought to be believed for its own sake. I am a Christian because I believe Christianity is true. I am happy to answer any questions you may have about anything in this regard. The philosopher/theologian I look to the most is St. Thomas Aquinas. You will not find a more organized and coherent thinker, but it may be challenging to begin with his writings directly.
As for how you can make a positive impact on society, here is a thought: find a good woman who will make a good wife and mother, get married, and become the best father you can be. One thing our world desperately needs is good fathers. The family is the foundation of society; so if you want to have a positive impact on society, what better way to do that than to work at its foundation?
It's a lot of responsibility, and being a father is one of the two most important jobs in the world; the other, of course, is being a mother, but you're not cut out for that role. No offense.
It is also one of the most difficult, grueling, endurance-testing jobs on the planet. You will feel like the whole world is against you sometimes, including your wife and children. You will feel discouraged and alone as you try to shield your children from negative outside influences, seemingly in vain. The initial amorous feelings you feel for your wife will fade, and your love and devotion will have to go deeper, beyond externals, by an act of commitment, or else it will die. That is when the virtues of the Stoics will be necessary: courage, wisdom, temperance and justice. In Christianity, there are the theological virtues, which I think are equally indispensable: faith, hope and love.
As far as I can tell, Stoicism is based on the idea that only material exists, and that the goal of life is to achieve serenity or happiness through virtue. I find the materialist aspect to be unsustainable intellectually. There are so many reasons I have come to believe that there must be a transcendent, immaterial Prime Mover. Not only that, but in the absence of a personal God, there is no reason you ought to become more. I use ought in an unqualified sense. According to Stoicism, you ought to be wise, courageous, temperate and just if you want to achieve happiness. But if there is a personal God, then there is a personal relationship at the source of our being, and we owe it to God to be the best we can be.
Many people mistake Christian ethics as law-based and duty-laden. According to traditional Christianity, true ethics is virtue-based, similar in many ways to the ethics of Stoicism. The main difference is love: self-sacrificial willing the good of the other. The perfect revelation of this love and all the virtues is Jesus on the Cross. That moment is also the perfect revelation of the heart of our creator God, one who loves us, not merely a Prime Mover, but one who moves and creates through love. Jesus could not have been a Stoic, and a Stoic would not have understood what Jesus was doing. Cato the Younger could kill himself in the face of tyranny for the beauty and goodness of his ideals and honor; it took God to die for corrupt, half-hearted criminals and sinners. Stoicism teaches that God is reason; Christianity teaches that God is reason, too, but also love. God is not just a cosmic engineer, but also a Father and a Bridegroom.
I realize that might be a lot to take in. Maybe you were hoping I would just tell you to join the military or go for that PhD. Those are good things, and I wouldn’t advise against them, but I can’t necessarily recommend one over the other for you. But I do admonish you to seek truth at all costs and to seriously consider taking on the biggest challenge you could face, that of fatherhood.