I have no problem with the evolutionists positing their ideas as a working assumption, i.e. as a possible solution. But they move from science to faith when they insist that it must be a necessary solution.
If it turns out that no material cause can be found, so be it ...
This is my point, there may be a point where the natural sciences should simply respond "we do not know."
Indeed, and it is "faith" as they define it: a blind intellectual leap that flies in the face of facts and is therefore anti-science.
Ah, but it's not really a solution at all, merely a tool to facilitate investigation. The difference is the difference between methodological naturalism and philosophical naturalism. The philosophical naturalist says "The material is all that there is." The methodological naturalist says "We will behave as though the material is all there is."
Science is about investigating the material world, and for that, methodological naturalism - the assumption that material events have material causes - is an absolute prerequisite for science, because science cannot proceed into the realm of the non-material. That's not what it's for, and not what it's about - science is about the material world, and must necessarily restrict itself to investigating the material world thus. It does not declare that the material is all that there is or all that there must be, it only says "the material is all we will investigate".
This is my point, there may be a point where the natural sciences should simply respond "we do not know."
But never a point where one should stop looking - you may have to settle for "we do not know...yet". ;)