Theist "You are Evidence" argument.

[truth_seeker]

I love this weird, inverse argument from ignorance, because it's so easy to debunk. While I agree it's no good to assume complete knowledge of a given field at any point, I also must point out that we can only form our conclusions based in the data available at the present time. Saying "yeah, this looks like bad design, but we don't know, maybe there's a good justification!" is exactly as fallacious as your Kelvin quote there: Kelvin assumes there's nothing more to discover, and you're assuming that there is a specific thing to discover. You're both doing so on the back of precisely zero positive evidence for those propositions, which is what makes them irrational.

All am saying is, especially when discussing the presence/absence of evidence for something, it is best to keep an open mind and take into account the very real possibility that we don't really know everything that there is to know about the topic. This is how human knowledge increases and progresses further. And that's how true objective science is made. Child-like inside-the-box arrogance gets you no where.