It’s funny how everyone tends to assume that there is a very obvious and well-known reason why we age, and people are usually shocked to find out that, like the article demonstrates, science kind of doesn’t really know. We know a lot of the mechanisms of course and I’m sure any doctors here can explain them, but it’s not like there’s one simple and universal explanation.

But we totally do!

There are a handful of mechanisms that break down over time, and they are both well documented and no new one has been found in somewhat the last 45 years!

Some people like to split some of them up in two, but the base SIX reasons we age are as follows:

• Cell loss/tissue atrophy
• Cancerous cells
• Mitochondrial mutations
• Intracellular aggregates
• Extracellular aggregates
• Senescent cells

See for example the book Ending Aging by the worlds most renowned bio gerontologist or the SENS foundation.

Fun fact, active research into how to fix them is ongoing research.

Thanks very much for this response! Good information for people like me who are interested to read more.

I think the point I was trying to make is that there are multiple reasons instead of one, and none of them are simple or easy. Understanding how those six things happen is subtly different to asking why they happen, which might be why we’ve got such a range of comments here and why the scientists in the article couldn’t agree on their answer.