Several years ago (I say ‘several’ and that’s what we’re going stick with!), something relatively important happened in my life. I became a legal adult.
One morning, I woke up (I was born 18 years earlier at 4 in the morning) and I was an adult. I had to fill out this card that said I could be drafted. I was able to walk away from my parents (if I wanted to). In some states, I was allowed to drink alcohol.
But, really, what was different. I was still the exact same person I was 8 hours earlier when I went to sleep. I wasn’t granted this font of wisdom (if anyone else was, then let me know who to complain to). I was still this dumb-ass kid who had no real idea about the world or anything in it. But NOW, I could help decide the future of our country in a process called voting.
The reason I bring this up is because of the similarity with a lot of other things that humans do. I used to live in a town in SE Texas. Get on a certain highway, drive for a few minutes and you would be in a different state. There’s this big sign that said “Welcome to Louisiana, the Sportsman’s Paradise”. In spite of the fact that some laws changed pretty radically when you crossed that invisible line, in reality nothing changed. If that sign didn’t exist, you’d have no way of knowing. Unlike what would happen if you took the highway in the other direction, because it was swallowed by the Gulf of Mexico several years before and literally ended in the ocean.
That’s a real boundary. You know when you transition from land to water (well, most people do).
It’s like that with biology to. There’s no real boundaries. Life is a continuum. In spite of the fact that I enjoy taxonomy and cladistics, it’s all an exercise in futility. There will always be exceptions.
For example, one rule is that species can’t breed with other species and have grandchildren. Donkeys and horses are different species because all mules are sterile. Lions and tigers are different species because… oh wait… liligers. These are the grandchildren of a lion and tiger and the children of a liger and lion).
Consider life. What is life? What does it mean to be alive. We can’t even define life accurately. In a book I read some time ago, there was a discussion of what life actually was. And in a conference hall with dozens of biologists, there was no single definition of life that someone couldn’t find an exception for.
When I was a high school student, we were taught that life has the following traits: reproduces, metabolizes, composed of cells, grow and respond to their environment, adapt to the environment and have levels of organization.
Firs that ‘cell’ thing is kind of Earth-life-centrict. It also says immediately that any AI we develop cannot be alive. But that’s a whole ‘nother ball of wax.
But using these traits, an apple is not alive. The tree it came from is and the gametes in the apple seeds are, but the apple itself isn’t. Yes, I’m being really nitpicky, But that’s the way things are. We pick nits.
When the government declared me a legal adult, they didn’t ask if I was ready. They didn’t give me a test. It’s a deceleration. It’s important for the benefits that deceleration provides, but that’s about the only way you could decide if someone was a legal adult.
Adulthood is like life. We know it when we see it, but we can’t really define it. Because there will always be exceptions to whatever definition we try to force. So, the government just said “this age is it”. Whether you’re ready or not.
Life is the same way. We know it when we see it, but we can’t really define it to the point that it is all-encompassing and there are no exceptions. In reality, what we do is say “this is alive”, “this isn’t alive”, “this is alive”, and on and on and on until the person we’re teaching gets that pattern recognition thing. In reality, I think that we make some a series of questions. If something ever answers yes to that series of questions, then it’s probably alive. In case of the apple, it is made of cells and it came from something that is alive, so I guess we can call it alive.
I used to play a game like this with my classes. Describe a “cat” to a person that has never seen or heard of them before. It must be sufficient that they can always pick out a cat, but never get a false positive (like a from a dog or a civet). In the end, we never could do it satisfactorily. We got some real good ideas though. It’s really hard without going into deep anatomy that the casual observer couldn’t use.
Another guy I know (I can’t recall if it was on this blog or elsewhere) did the same thing except explaining humans to an alien. Say an alien species came to collect life forms to study, but they weren’t allowed to collect sentient organisms. Can you describe humans such that the alien could always correctly determine human from non-human? I think we tried for a month or so. There was always an exception that someone could think of.
My last attempt was evolutionary based, while it was a perfect answer, no one would be able to determine that level of family history.
I think I had a point somewhere in there. Humans like putting things into boxes. But we don’t like it to be too hard and when it is hard, then we go with a ‘close enough’ kind of approach. We also have some pattern recognition schema that’s difficult to describe. Even my boy, when he was 5, could always identify a dog and a cat and never mixed them up. I have no idea how we actually do that.
I’m pretty sure we don’t point to a single feature and say “that is the defining character”. But when we deal with other continuum based concepts (like maturity), we do draw a line in the sand. Cross that line, you’re an adult.
Think about it. How would you define an adult?