Jacob Kimmel

So you end up with this happy medium, but that limits your total step size.

And then the number of variants you can screen in parallel is basically limited by your population size.

And so for most of evolution, there were lots of forces constraining population size as well.

One of the dominant source of selection on the genome is really prevention of infectious disease.

And it seems like when you study the history of early modern man, infectious disease is actually what shaped a lot of our population demographics.

And so there's a lot of pressure pushing for those step sizes, those updates to the genome, really to be optimizing for protection against infectious disease rather than other things.

And so even if you imagine that maybe the arguments on the former and the first and the second of these possible, you know, positive selection being absent for longevity and potentially some negative selection existing.

You could, I think, construct a reasonable argument for why humans don't live forever, why the genome hasn't optimized for that, simply based on these optimization constraints.

You have to imagine not only that the positive selection is there and the negative selection is absent, but that when you think about sort of the weighted loss term of all the things the genome is optimizing for, that the weight on longevity is high enough to matter.

And so even if you imagine it's there, if you simply imagine that the lambdas are dialed toward infectious disease resilience more effectively, then you can construct an argument for yourself.

And so I think really when you start to ask, why don't we live forever?

Why didn't evolution solve this?

You actually have to think about an incredibly contingent scenario where both the positive selection is there, the negative selection is absent.

And you have a lot of our evolutionary pressure going toward longevity to solve this incredibly hard problem in order to construct the counterfactual in which longevity is selected for and does arise in modern man and in which we are optimal.

And so I think that puts human aging and longevity and health really in this category of problem in which evolution has not optimized for it.

Ergo, it should be, relatively speaking, relative to a problem evolution had worked on, easy to try and intervene and provide health.

And I think in many ways, the existence of modern medicines, which are incredibly simplistic, we are targeting a single gene in the genome and turning it off everywhere at the same time.

And yet the fact that these provide massive benefit to individuals is another sort of positive emission or piece of evidence.

Yeah, it's actually an excellent question that I haven't heard posed before.

So we think about where do antibiotics come from?