Aging is the price paid for the ability of experiencing existence, one might philosophize.

Natural cellular aging begins with differentiation. Once a stem cell becomes a specific cell type, it’s locked in forever: fat cells can never become muscle cells, no matter how hard one wishes, or pokes and prods at them in front of the mirror.

Or so it goes in nature, but scientists can definitely transform cells, as if biologically compensating for all the failed alchemical attempts of the past.