PT158 · S2 · Q21 A geologist recently claimed

Whether known bacteria engage in sexual reproduction is irrelevant to whether nanobes are alive. Nanobes aren't bacteria. If this answer were meant to imply that bacteria isn't complicated enough to reproduce, then it would probably strengthen the argument. We know, in reality, that bacteria is a form of life (there are other forms of reproduction besides sexual reproduction, such as asexual reproduction). But if we thought this answer was saying that bacteria isn't even complex enough to be life, then that would support the author's notion that nanobes, 1/10 the size, are also not life.

If we were told about something as small as a nanobe that WAS a form of life, then that would badly weaken. These remains of bacteria are as small as a nanobe, but we're not told they're alive. They are "material phenomena". They might just be a fragment of a bacterium. The bacterium is a form of life, but the fragmented remains aren't necessarily life.

We aren't talking about previous definitions of life. The author is yielding the current definition of life, one that includes as a prerequisite that an entity has a reproductive mechanism. And for all we know the previous definition of life ALSO held that any form of life must have a reproductive method.

This is saying you can be bigger but simpler than some other animal. Being bigger doesn't necessarily mean you're more complicated. Being smaller doesn't necessarily mean you're less complicated. Could we stretch this to say, "Being smaller than bacteria doesn't necessarily mean that nanobes are less complicated than bacteria"? No, that's a big stretch. This is just one example about some cold-blooded lizards, not a rule of life we can extrapolate to the microscopic scale. At the scale of lizards and other animals near their size, everyone is WAY big enough to have DNA, a reproductive mechanism. We're talking about a thing that is INCREDIBLY small, potentially smaller than DNA itself.