Upon Further Reflection...

based on the act of bending my thoughts back (for a second time) and pushing them forward to a greater degree...

... mentally "re-bending" my previous thoughts, examining them from a new angle (the "bending back" of reflection), and doing so for a longer or deeper period (the "forward progression" of further - hopefully), which then becomes the foundation (upon) for a new or revised conclusion - which in all honestly is indistinguishable from the mud our ancestors had to endure ...

upon further reflection (the "etymology" of the title) reveals the mind as our mirror, actively turning to catch the light of an idea from a new direction to see it more clearly, as it comes to form, over and over again, and into new thoughts surrounded by light forms and previously conditioned experiences