Is Life Just Different?

Thank you, Samir.

So Phil, what's the big idea?

I'm arguing in this piece that it can be valuable, perhaps even essential, to think of living organisms as having this property of agency, and that property refers to the fact, if we come back to your example of a hurricane, the thing that makes living things different from a hurricane, given all of those similarities, is that living organisms do things for reasons.

They have goals.

They have purpose.

The hurricane has no purpose that we can meaningfully think of, but living things do.

They are trying to achieve particular goals, and I think it makes sense to really think of them as trying, even if that doesn't involve any sort of conscious reflection.

So that's what we're speaking about when we talk about agency.

It's a way of acknowledging and thinking about, and perhaps even theorizing about, this property of living organisms that has always kind of troubled biologists, that life seems to be teleological, that it has goals, that it does things for reasons.

So the idea of agency is really saying, "Let's [laughs] stop running away from that.

Let's just recognize that this is the nature of life, and try to see whether we can turn that into a useful and a meaningful scientific idea."

There's so much to unpack here, and I can already see the places where this is gonna get contentious from a scientific point of view, but I wanna start, as we often do, with a few definitions.

Is it a useful exercise for us right now to define what we mean by life? I know that that's not [laughs] an easy question to answer.

Well, it's certainly one that hasn't been answered, because there is-

Yeah

... no consensus definition of life.

You can start making a kind of shopping list of things to look for, like self-replication and metabolism, Darwinian evolution, but that doesn't really get us very far, because what if we find a system like a hurricane that has some of those things, but not all of them, and how do we know that we've got all of the right things on that list? It's very hard, if we make a list like that, to exclude everything we'd like to exclude, things that we feel are non-living, and to include all the things that we'd like to include.

So what I'm suggesting is that perhaps rather than trying to think about what is living and what isn't, it might be more useful to think about what has agency and what doesn't.

I mean, if we think about viruses, for example, that's where a lot of these arguments get really contentious.

Are viruses really alive or are they not? Rather than trying to get a yes or no answer to that question, I think it makes more sense to think about, when do viruses have agency? When they're in an infected host, they have agency.

When they're not, they're like a little clump of chemicals.

They're just proteins and nucleic acids that don't do anything.

So I think that the idea of agency can perhaps help us to crystallize what's special about life without us having to wrestle with this question of how to define life itself.