Dave Bonta's "Supposition" asks us to try on a strange idea: that each of us carries a second presence inside, moving and sitting in perfect step with us. The speaker admits he doesn't like thinking of bodies as "mere vessels — or vassals," but he plays along anyway, repeating "suppose it's true" like someone testing a thought out loud.
What makes the idea appealing is how much it seems to explain. Our urges to hold someone, or to vanish into deep concentration, become the inner self reaching for another inner self. Aging turns tender rather than sad: white hair, a glimmer behind the eyes, and cracks in the skin that let an "inner blue" show through.
The ending shifts the question. Even if heaven were literally inside us, the speaker wonders, would that be as illuminating as knowing we rose from the ocean and came down from the trees? The mood is curious, quiet, and quietly awed, more wonder than doubt.