Is atheism a scientific perspective?

[The Grand Nudger]

And when did evolutionary forces produce higher complexity?

You mean, other than the evidenced examples....of...for example...every living thing?  Unless, ofc, your "higher complexity" is a floating trashcan term.  Are human beings more "complex" than single celled organisms? If the answer you would provide is yes, then you've answered your question..if it's no, you've rendered your question meaningless.

And for the third time, I am not saying that design is the only cause. I'm saying that it is the only known cause.

You keep saying it, but it's no more true now than it was the first time.  That's kind of the problem.  

There has been a thorough search, but obviously not all possibilities have been considered. So we literally have to investigate every possible explanation for any observation before we can say that we believe one stands out as best?

"We" wouldn't have to do that, a known explanation already stands out as the best explanation.  All available evidence poins to it without a single dissenting peice of evidence.   You might have to, though, since you'd rather not refer to the theory we have.  

And I've used positive evidence. We see intelligence creating information all the time. Scientists are constantly creating RNA sequences in the lab to guide CRISPR-CAS 9 machinery. If I go back to my university and create a functional protein by linking a series of amino acids in a desired way, then will I have given positive evidence that intelligence is an adequate cause?

Indeed, which isn't a problem forevolutionary theory - it's kind of the crowning achievement, and is only accomplished by leveraging evolutionary theory.  You can't really refer to their success without tacitly approving of the body of knowledge they use to accomplish it.  Are they achieving consistent results by accident, by leveraging an incorrect theory?  It's happened before, just figured some clarity was in order.  Did "god" do it exactly like modern synth did it?  What's the problem?

I believe that the designing intelligence is God, but that is simply not the type of claim that ID is making. There are ID proponents who do not believe this.

Actually, that -is- the claim that ID made, which is why it appeals to you..unfortunately, they failed to support that claim and ultimately discredited themselves by hanging their hats on an irreducible complexity that does not exist. Meanwhile modern synth continues to collect evidence...there is still no evidence to the contrary, and it produces results like crispr, above, that you seem to be quite enamoured with. I can't, for the life of me, figure out how it is you're trying to argue -against- modern synth by presenting a litany of corroborating points of data for the theory with which you have a religious objection to.........