That is certainly an important question. It’s not the kind of question that science helps us answer, though. Science tries to explain the world in terms of causes, such as why animals behave in certain ways, or what causes a particular disease.

Other fields of study, such as philosophy and religion deal with the meaning of life.

That doesn’t mean that scientists can’t have opinions about why we exist. We’re just not experts in that field. So here’s my personal opinion. It may not be better or worse than anyone else’s.

My opinion is that we get to decide why we exist with every decision we make and every action that we take. That doesn’t mean we have to be perfect. Nobody is. It just means that it’s important to figure out what we value and try to make decisions based on those values. I know that I am still less kind, honest, or generous than I should be sometimes, but I try to keep my values in mind and do the best I can to honor those values. When I act on my values, I make my existence mean more.

My suggestion is to think about your values. What’s important to you? What do you think will make the world better? Why? Talk it over with people you trust.

Then think about anything you could do to make even the smallest change. Do you wish people were nicer? Be nicer to people. Do you wish your neighborhood were cleaner? Pick up some trash. Start small.

Just remember that your existence is very valuable. It’s up to you to decide what to do with it.

As far as science can tell, you exist because the laws of chemistry, physics and biology allowed certain chemical reactions to autocatalytically take place around 4 billion years ago. These reactions allowed metabolic reactions to occur along a mineral surface or within a vesicle, and those metabolic reactions allowed replication to spontaneously occur….

Once such a self sustaining protobiology emerged, this protobiochemistry interacted with the environment such that the set of reactions that were favored continued whereas the ones that did not were de-selected. This aspect is a protoform of Darwinism… the selection of an organism due to interaction with the environment….. After 4 billion that is 4,000,000,000 years of this selection process (darwinism), POOF!! , here you are.

There is no reason to suspect that this process has not taken place on tens of billions or more planets within the Milky Way galaxy, a collection of around 200+ billion stars. Note also that the Milky Way galaxy is only ONE of perhaps a trillion OTHER galaxies within the observable Universe.

No matter what, you should strive to make something of your life and help others insofar as you can do the same. We are all in the same boat and you should be kind to others who may not be as fortunate as yourself.

You're not alone in asking this question - I think that every single human being asks this question at some point in their life. Truth be told, we don't know - but we are trying our very hardest to find out! Every new discovery, and every new breakthrough in science can hopefully help to get us closer to the answer. We may never truly know why we are here, but the pursuit of discovery gives us purpose - and that alone just may be the answer itself.

I know that's not a very satisfying answer, so in the meantime... the answer is 42. Unquestionably and always 42. Don't Panic!

The simple answer is, because you were born. The longer answer could be that Earth has the right elements and is the correct distance from the sun to support life, so life evolved here, and eventually there were people who gave birth to more people, who gave birth to your parents, who gave birth to you.

Getting more philosophical, there are lots of ideas about people's purposes in life. Some of them come from religion, and some are ideas that people just decided make sense for them. Generally, most people's purpose has something to do with doing good things.

The simple answer is that your father's sperm met your mother's egg and fused into a single cell, that single cell being you. That one cell then grew to become the person that you are. We know this because this is how all humans - and most other animals - are created, by a sperm meeting an egg. We've seen this happen in nature and in the laboratory many, many times, and are not aware of any way to create humans or most other animals that are different from this. As a result, we conclude based on what we know that this is how humans come into being.

This question is often asked in a religious context, such as "did God create me?", or the like. From a scientific prospective, the best that we can say is that there is no evidence for supernatural forces involved in creating humans, and the science only works when there is evidence. This is the weakness of the scientific method; while it is the best method we have for learning about the universe when we have evidence, it fails when we don't. As a result, science cannot answer religious questions like the one that I asked three sentences ago.

All that we can say is that the simplest explanation for your existence, what we actually have evidence for, does not require anything supernatural.

Science can help to understand a bit about yourself, why you are the way you are, and how you came to be. You started from a single cell, a fertilized egg that contains genetic material (DNA) from both your mother and father. In an amazing processes, that single cell grows and differentiates into many millions of cells that become tissues and organs such as lungs, brain, heart, muscle, liver, skin, and so on that make up the anatomy of a human. All this development took place inside your mother’s womb, and after you were born, your brain continues to develop and grow as you learn and experience the world. The field of science that studies how organisms develop from single cells to adults is called developmental biology and is a fascinating field.

But there is more to us than just our biological functions. Humans have highly evolved brains that produce complex thought, consciousness, feelings, emotions, and a sense of identity. The branch of science that studies how the brain can give rise to feelings and thought, and how your personality and identity develop is called psychology. While scientists don’t fully understand consciousness, psychology can help to understand how your mind can turn a constant stream of perceptions into a single unified “I” with complex feelings, emotions, and beliefs.

In addition to having a sense of self, humans live in communities of people, and we are always interacting with each other. Everyday you will interact with members of your family, friends, classmates, and others. These interactions with people shape who you are, your values, and who you will become. The branch of science that studies how and why humans behave in society is called sociology. Sociology can help explain how and why you exist as an important member of your family and fiends.

Finally, from the moment you are born, you are immersed in a culture that is particular to a specific time and place in the history of humanity. The study of how culture develops and how different societies interact is called cultural anthropology. Cultural anthropologists study how meanings and beliefs are similar or different in different groups of people in different places of the world, and how these change over time.

Thus, science can help to understand how and why you came to exists as a biological organism (biology), as a thinking/feeling subject (psychology), as a member of a family/community (sociology), and as a person immersed in a particular culture (anthropology). At the individual level, people find meaning by thinking and reflecting about their beliefs and desires. At the social level, people find meaning by being part of a family or community. At the cultural level people find meaning by participating in important cultural practices like attending sporting events, participating in religious ceremonies or national celebrations, eating and sharing a meal that has a particular cultural significance, and so on.

Culture gives rise to art, literature, and religion. In this context, science can provide only a small piece of the answer to the question “Why do I exist?.” There are many different ways that people have attempted to answer that question. Literature, philosophy, religion, and the fine arts all attempt to answer this question in their own way, and all these disciplines can be important for helping to think about what it means to exist and what it means to be a human being with a meaningful life.

I'll say you exist because your mother and father gave birth to you, and their parents gave birth to them, and on back for generations and generations. 'Why' questions can be hard to answer. What do you think we can do with our lives?

It’s good you’re wondering about this at your age. Essentially, we all exist to make the world better. Keep asking questions like that and you will be on a conscientious path.