I would say that a hypothetical discovery of nanotech on the moon would be evidence of alien life
Even though it can be explained in evolutionary terms just like life on Earth?
Unfortunately that is where the analogy ends because there is an important distinction between what is natural and what is artificial.
Nope, there is an arbitrary distinction between what is natural and what is artificial, a circular definition that says life is non-artificial and only the non-artificial can live.
If they case that this hypothetical technology was so advanced as to be indistinguishable from natural life then I would take that as evidence of evolution on another planet.
Even if scientists insist that this technology can all be explained by applying Darwinian principles?
Perhaps you could give an example of your hypothetical in-organic evolution on earth, incidently there is an example of organic molecules giving rise to self replicating machines - DNA.
Dawkins claims he has achieved inorganic evolution (lookup memes, I think), also some scientists have applied evolutionary principles to electronic design. There is no reason at all to suppose that Darwinian principles, if they work, shouldn't apply to inorganic processes. And no, there are no examples of organic molecules spontaneously giving rise to working DNA.
You are missing the point in your analogy, since the supernatural is by definition automatically discounted within science then no amount of scientific evidence can prove that god did it.
Actually my analogy is about little green non-supernatural beings, and my question was all about whether we would accept evidence of design in complex mechanisms as being evidence of alien intelligence, even if there was an alternative Darwinian explanation.
If you can provide some evidence of a designer that could not be alternatively adequately described by evolutionary theory then I would be intrigued to hear it
There, you said it. Let me rephrase your statement in reference to the nanobots: "If you can provide some evidence of alien intelligence that could not be alternatively adequately described by evolutionary theory then I would be intrigued to hear it". In that scenario, do you regard this as a rational statement?
but the simple fact is that you can't because there is no such evidence.
Surely the evidence is staring at you in the face: a whole race of nanobots on the Moon that look for all the world like they were designed.
Everything that has been put forward by the proponents of intelligent design (what a misnomer!) has been roundly discredited by real science.
I'd say it's more likely the nanobots were designed by an alien intelligence.