Detecting design or intent in nature

[Esquilax]

Intellect is a faculty which humans possess but there is no strong reason to believe it is exclusive to humans. We've observed but a tiny fraction of reality so we should have little confidence that human intellect is the only intellect which exists in reality as your argument suggest.

Oh, so we're only bound to consider possibilities exclusively by observation when it suits you! Gotcha.

Either modulate your argument so that observations aren't the only means by which we can probabilistically determine the origin of something, or stop using the argument, but don't special plead and pretend you're arguing consistently when you're not.

On the otherhand if evolutionary systems on this planet can exist sans intellect we should observe them coming into existence on this planet sans intellect. We don't. We have we have explored and observed this planet in great detail an it appears that evolutionary systems on this planet can only come into existence with the help of intellect.

But there's only one "evolutionary system" in existence in the natural world, for which every being it produces is a part of that broader system. It's not so much that we don't observe new systems coming into being naturally, but that when they do they are enfolded into the much older, continuous system that has been producing life since the beginning of it on this planet. Your argument for why we should exclude natural means on earth is complete nonsense.

The worst part is, even if your argument actually functioned- and you don't really seem to realize why it doesn't, just yet- you would still be falling victim to a number of fallacies that have been pointed out to you in the past, not the least of which is that what you're committing here is an argument from ignorance, that can be demonstrated to be wrongheaded with one simple sentence:

White swans cannot exist because I've only ever seen black swans.

You really are just fractally wrong here, Woody: everything new we have ever discovered was unobserved before we discovered it.