We humans are all alike and we are all unique.
We love. We hate. We talk. We touch.
We wear clothes (most of us). We sing songs. We dance and we give gifts. We seek out water and meaning. We take care of the next generation.
What is "culture?" There are simple answers, and there are difficult ones. Any given culture is a set of symbols. The space of all possible cultures is a subset of humanity's behaviors and perceptions, but just how large is that subset?
Obvious examples of culture include art, music, dance, theatre, food, and language. Others include relationship dynamics such as patriarchy versus matriarchy, monogamy versus polygamy, and egalitarianism versus capitalism. All of these can provide a window into a specific people's worldview.
An economist might say that a culture is a set of reasonable expectations which enable cooperation. We take these expectations for granted, but they are everywhere. You don't crash into other drivers because we all agree on which side of the road to drive, and on the meaning of red and green lights. We have norms for commerce, social interaction, and scientific exploration, and perhaps everything else we humans do. These norms make our lives more efficient, but they can also be the source of comedy. In my travels I've said some things that were very, very wrong -- unintentionally, of course.
We find culture interesting because it highlights our differences. We enjoy discovering things that are universal to all humanity, but do such things comprise culture? Human behavior can be described as a complex path-dependent interaction between instinct and learning. All humans blink, sleep, and yawn -- it makes no sense to consider these in the domain of culture, but is smiling culture? Pointing at something with your finger? Nodding your head to mean, "No?"
Culture is passed down from one generation to the next. It changes and evolves. As a community evolves, it drifts further from its neighbors. Each community's culture becomes slowly distinct from the others. It is only through this evolution that we learn to distinguish that which comprises culture from that which is innately human. What if some of our human "universals" are merely universal by accident? Perhaps there are untried modes of living that would be just as comfortable and fruitful as our current ones. Could there be "better" cultures that no group of people has ever dared explore?
Culture is almost always arbitrary, but also beautiful. My life, so far, has been a journey in understanding other cultures. I love them. I also have new love for my own.