I am the universe experiencing itself from one particular angle.
The manner in which the physics of the early universe unfolded led to complex combinations of interacting particles, of which carbon is readily produced by stars. Stars being readily produced by reef galaxies.
As such it is no surprise to find that when a star ignites within a sufficiently enriched cloud of material (by the death of previous generations of stars) that there is energy freed to initiate various forms of interactions.
One curious quirk of carbon is that it interacts in interesting manners when liquid water is present with certain impurities, and self-reinforcing feedback loops can autocatalyze. Given enough time, eventually a feedback loop will find a way to not just stabilize its own structure, but to reproduce it, and lo' life as we know it starts.
After that it is just a matter of the various energy demands induced by the shifting positions of the continents, and the energy reaching the planets surface. The ability to reproduce led to competition for resources, natural selection, evolution, and a few scant mega years ago the uplift of the mountain ranges around the rift valley in africa led to formerly tree dwelling apes wandering around in grasslands, seeking new sources of food.
Their awareness, as has been common for many lifeforms, in particular the vertebrate line, was designed to recognize other life which may both be edible, and aggressive.
Quirky adaptations such as social recognition, organisms being something besides food or predators, but instead cooperative partnerships on a more deliberate level than the original symbiotic types.
The demands of the cycling ice age era that resulted from antarctica settling at the south pole (thus limiting the circulation of heat globally somewhat) led to a selective pressure favoring curiousity, problem solving, and in particular the use of tools.
From there the modern humans eventually wandered out of the grasslands, and in a geological blink of an eye reached the present state, with a very high population density.
As such it is far more likely that I would be alive now, as opposed to then, if I were to find myself as a human observer. The ability to recognize that my self is different from others is useful for social interactions, but it is also an artifact of our macroscopic size scale induced by the carbon biological processes.
It is not useful for a grassland ape descendant to identify itself as being located in multiple positions, or as multiple individuals, so it is not odd to find us "locked in our own heads", but nonetheless I have multiple selves which I identify myself as.
I am Max™ here and on several boards, I am Max Thyme on others, I had another birthname which I discarded years ago, I have online game personalities, pen and paper RPG identities, and it is arguable that the "me" I seem to observe when I dream is distinct from the "me" I observe when I wake.
I am not connected directly to your sensory systems, but if I were able to receive the proper input from both of our sensory suites, I would argue that I was both of us, would I not?