Our astitva (existence) is solid because of our asthi (bones) only; for you can imagine ourselves as a lump of flesh and fat otherwise. The deciphering of this astitva was also feasible because of our asthi only, this is because these asthi leave impressions as fossils-records into the strata of the Earth, whereas other stuff melts away into the Earthen-clay.
So, it is often and wisely said that we should not be boneless persons, i.e. we should exist sensibly.