[crescendo]

Right now we're all communicating across a tiny rock in the middle of nowhere. Yet we have the rational means (linguistic, mathematic, scientific) to ponder the depth and extent of our own existence.

Maybe the ability to "ponder the depth and extent of our own existence" isn't really such a big deal after all. As humans we tend to exalt the things that separate us from other species on this planet without much analysis as to why those traits should be exalted. What if such "pondering" is just the brain's way of filling in idle time with junk to fool us that something is there, such as when it fills in areas of low resolution in our visual field to fool us into seeing a full picture?

The concepts of "ponder", "depth", and "existence" originate within the human brain, as does the very concept of "concept".

I'm not saying your statement is wrong, really. Just pointing out that you're making a big assumption that the act of pondering existence and the like are some kind of mystical thing.