Joined: Mar. 2005
If that's saying that the snowflake analogy is ineffective because snowflakes don't reproduce, then I have to agree. That particular analogy doesn't work.
IMNSHO, it's not whether "complexity" is defined, it's whether there's some evidence based reason for thinking there's some limit to increases in complexity within things that reproduce themselves. As far as I can tell, it's absurd to think that something with a level of complexity wouldn't be able to add a few more details to what it has, which by any definition I'm familiar with, would mean an increase in complexity. In the case of living things, I'd think the energy requirements, and sources thereof, would be the limiting factors, not the number of details in the construction of the organism.
(Or if discussing abiogenesis, they'd need an actual reason for thinking there's some boundary that can't be crossed without help, to get from non-reproducing chemistry to self replicators of some sort.)