Editing Twin paradox (section)

==The equivalence of biological aging and clock time-keeping==
All processes—chemical, biological, measuring apparatus functioning, human perception involving the eye and brain, the communication of force—are constrained by the speed of light. There is clock functioning at every level, dependent on light speed and the inherent delay at even the atomic level. Biological aging, therefore, is in no way different from clock time-keeping.<ref>{{cite book |title=Spacetime Physics |edition=2nd, illustrated |first1=Edwin F. |last1=Taylor |first2=John Archibald |last2=Wheeler |publisher=W. H. Freeman |year=1992  |isbn=978-0-7167-2327-1 |page=[https://archive.org/details/spacetimephysics00edwi_0/page/150 150] |url=https://archive.org/details/spacetimephysics00edwi_0|url-access=registration }}</ref> This means that biological aging would be slowed in the same manner as a clock.