"On the other hand, there are good reasons to think that consciousness resides in the physical (for example, it can be affected/suppressed/extinguished by anesthetics), and zero reason to conclude that it resides in some undefined "metaphysical"."
I don't think you understand the "problem" of consciousness.
You can talk about *my* consciousness "objectively," but you have no way of knowing by "scientific methods" that *my* consciousness even exists, i.e., that I am a conscious being.
As for *your* consciousness, *I* have no way of knowing that it exists, but I assume that it does (otherwise why would I bother to reply to you?). But from your perspective, the entire world exists within your consciousness. The world you "see" is really just the image in your brain that results from the light that enters your eyes. So what you "see" is really inside your head. In other words, you cannot distinguish between what you call your consciousness and what you call the outside world.
And that outside world includes "science" itself, by the way. You cannot "put consciousness under a microscope" because the friggin' microscope itself exists within your consciousness! Everything does.
On a side note, here is a link to some theories about how life formed on earth...I'm not putting my name on any of them or anything, just a little FYI, if you care to peek.