Well... by definition, random mutation cannot ever produce metaphysical phenomena, in the dictionary form of the world. And on the other hand, the metaphysical cannot interact with the physical. Otherwise it WOULD be physical. That is the problem of dualism.
The simple question is, can you see what APPEARS to be metaphysical as simply an extension of what you'd be willing to call physical. Like CrashFrog, I think pretty much every bridge can be built, easily. The only one that I fail on is the problem of "qualia" (not that we have subjective experence, but why it takes on the qualities that it does).
I think there still is an interesting question in what you're asking
In sum, if my puny neo-cortex really evolved; how could it be so metaphysically encumbered with things like singing hymns, making melodies, writing songs and poems, drawing paintings (like the one to the left), architecture, charity, FoxPro programming, etc.) ?
Ignoring the subjective accounting that these are 'metaphysical'... I think there's a point here that crash missed. Even if you view ALL of these things as symbol manipulations (and I would argue against that for untrained artists), there are MANY types of symbol manipulations that we DO NOT DO. In other words, it is still interesting to ask WHY we do THESE things, and not others.
The fact that we have brains that are able to process things symbolically isn't logically CAUSAL for us to play music. In fact, I can name at least one other symbolic processing device that does NOT do any of the things that you mentioned. And that's the personal computer.
But like I said, I have no personal motivation to look farther than the human brain. I would suggest reading some books about cognition before making that leap; we really know quite a bit more than you're probably aware of, and it might change your mind about the necessity of appealing to something beyond the brain.
Ben