Re: [ANN] SR/InertialFrames v2.2.1

which, apparently.  That said, thanks for asking:
 The "clock hypothesis", in simple terms, is the principle
that all working clocks tick at the same rate (the proper
time rate) in their own frame.  Drop that and you drop
any chance of doing any physics at all: together with
the use of light signals, clocks are fundamental to
contemporary physics and the very measurement process.
 It is also equivalently the hypothesis that the local
experience of time is universally the same for every
particle and every observer: and I do not actually
mean anything psychological, rather the rate of getting
old, just like the rate of atom decay, is a physics fact.
 And note that none of that is about inertial frames and
motion only: time proper ticks at the same rate every
time every place.  Indeed, time dilation and length
contraction are only relativistic effects, we know that,
don't we? "Nothing is actually slowing or shortening
aboard that ship", which remains canonical relativity.
 -Julio