You were born. You grew up, learned how to survive in a complicated and altogether bewildering world, learned a few things in school, maybe some more in college. And one day you face the challenge of your existence:
What should I do with my life?
First, let me assure you: you should be asking this question. Anybody who has ever achieved anything has asked themselves that exact question. (This last statement, by the way, is not supported by any data that I know, but it could be basically true anyway).
Before I will tell you what to do with your life (even though I don't know you), let me first tell you about your purpose.
You have no purpose.
OK, I should have defined "your purpose" more accurately. If we understand "your purpose" as your role in a grand design of things, you should know that there is no grand design of things. (For this there is data, but this is not the blog post to get into this issue. Just trust me here: "No Grand Design".)
Consider the purpose of a blade of grass. You've seen one of those. What do you think the purpose of the blade of grass is? Granted, it can't think like you and I can, but it is alive, and you share about a quarter of your genes with grass. Is its purpose to be eaten by a cow? To be shortened by a lawnmower? To give a nice green feel to the front lawn (in a cooperative quest together with its closely related brethren?)
You do of course realize that this thinking is absurd. The blade of grass just "is". It grew from other blades of grass, just like you grew from your parents. You had no choice in the matter, nor did your parents know what they were producing (beyond the obvious: "one human child"). Speaking from the vantage points of molecules, you're the result of some other molecules.
But compared to the blade of grass, there is something special about you. You can learn. (You can move also, something that the blade of grass will eternally be jealous about). When you learn, you take past experience into account to change how you will do things next time around. You can learn about the world in which you happen to be placed, and you are even free to ponder whether there could be other such worlds beyond the one you currently inhabit, populated with other beings that ask themselves what to do with their life.
This ability you have, to understand your place, your position if you will, within the entire grandiose universe, is something grandiose in itself. You can actually think about what it means to be alive, unlike the blade of grass, which just is. (And still has so many of your genes). Only you can actually ask yourself the question "What should I do with my life?"
We already established that you have no purpose. What you should do with your life is to give yourself a purpose. You see, as you are freed from some sort of grander design, it turns out that what you become is entirely up to you. You are the one who gets to choose your purpose. And when you begin to think about what purpose to give to yourself, look no further than your own dreams.
Dreams are curious things: we control them and don't control them at the same time. There is something in them decidedly from us, and sometimes stuff that isn't exactly how we thought we were. But we all dream, whether at night or during the day. But in our dreams, we often are what we long to be. This is the key:
Your purpose is to be what you long to be.
It's really quite simple. Granted, some people long to be King or Queen, when in fact they are not anywhere near the line of succession of any Royal Family. This is not the longing I am talking about. "I long to be rich", I often hear. Big deal, who doesn't. I'm talking about the longing that is based on something you experienced, something you learned, something inside of you that made you think: "This is what I want to do all the time". When you identify this, you know what to do with your life: to become the person who does precisely that. Imagine your best self, the one that has achieved all their dreams, and strive to be that person. That is the purpose of your life, in fact anybody's life.
"How do I do that?" is the next obvious question, and this one does not have a simple answer. Generally speaking, your life's path is determined (to a large extent) by many small decisions that you make, and perhaps a few big ones. If you don't pay attention, others may make those decisions for you.
Don't let them. This is your life, not theirs. They had their chance. This one is yours.
It is often the myriad of small decisions that nudge you closer to where you want to be, and those are the decisions that can be corrected if you realize that you are not moving where you want to go. Major decisions (getting married, accepting a job overseas, etc.) are more difficult to correct should you realize that they are not helping you reach your goals, but almost all decisions can ultimately be corrected. The trick in making more correct decisions than incorrect ones (because let's face it, that is the best one can hope to achieve) is to keep in mind the person and the life that you dream to attain. If this is the life that you want, then you must do what is necessary to get there, sparing no effort, fearing no obstacle.
Tell yourself: "So you want it. Are you prepared to work to get it?" Nothing is for free, at least not the things that are worthwhile. To achieve what is worth your while requires work. But work is easy if you really want the rewards. Find what you cannot live without. Find what is your passion. Working towards that will not even feel like work.
What if you have no passion? Then you have not lived enough, or experienced enough. One way to remedy that is to read about the passions of other great people. Not because you should be just like them, but because they might inspire you. Read about adventurers, scientists, leaders, artists. Read about their struggles, their passions, and their failures, and you will find your own. But by all means, read. Let me, for the sake of emphasis, repeat that. Read as much as you can.
There is a reason our civilization has started an exponential boom after we figured out the printed word. Inspiration is passed on from one person to another. If one dream can infect thousands of others, an exponential amplification is inevitable.
If you are asking "What should I do with my life?, you have already taken the first step to do something with your life. Take the next step. Find out about your passions by studying other people's passions. There is no doubt in my mind that you will come across a singular experience, written down by someone who used to be just like you, that makes you realize: "This is what I want. This is how I want to spend the rest of my life."
You see, you have only one life, and you're pretty lucky to have gotten one anyway. Use it wisely, because there are no do-overs. According to my view of the universe, when you're done you're done. So make it a life you (and your offspring) can be proud of. Strive to live the life that you were meant to live if there indeed had been a "Grand Design". I think you've got it now: you are the "Grand Designer".