I’ve recently turned 35, which is normally well beyond the age where one can safely assume one is an adult. I remember myself very clearly in my twenties — maybe even a bit too clearly — and I’m totally sure I wasn’t yet an adult when I was 23, for instance. Somewhere late in the last decade, a change has happened.

What changed? What part of me is now different from the 23-year-old me? The answer actually lies on the surface: interacting with the world of other adults has gotten much easier than before. The world of adults holds very tightly onto one notion that has now taken a common hold over all the different ways I think and do things. That notion is that everyone in the world is very different.

This may sound simple at first, but here’s what I mean by that. Accepting that everyone is different means you accept that you can never be sure or fully aware about other people’s motives, desires, intentions, feelings or thoughts. Even when someone’s behaviour seems familiar — this happens, for example, with someone you closely know — there can always be something very unpredictable they can do once and this still won’t come into conflict with the image of the person that you had in mind. You wouldn’t imagine or even think about someone doing what they did, but this still fits well with the rest of your image of them. The world is just so very flexible that it allows that too.

This manifests itself the most in the fields that are normally considered “very adult”. Take law: nothing can be taken as obvious and unshakable by a judge in court. They know too well that the factual evidence nobody could’ve predicted may easily beat some “obvious” assumptions. And in politics, no issue comes without a second side; everything is open to a new interpretation that has a chance of remaining valid even in the crowd of the old ones.

The flexibility of meanings and the ability to control it is clearly something that separates an adult from a child, or a teenager. Both teenagers and adults use the same words, but teens apparently tend to think that words have fixed and obvious meanings — that they know for sure how things are because “obviously” it can’t be any other way. Adults, on the other hand, can bend and control the meaning of the words they say. For them, it gets easy because there’s one thing you can be sure of: if you attach certain meaning to a word and release it into the world, you will be amazed with what new meanings it will get back to you.

I don’t remember exactly when this understanding has come to me — I think this was a slow process around the age of 27 — but that clearly was the end of my non-adult life.