is diametrically opposite
, since we know how to measure space. All we have to do is to verify the fact that the length of the curve
is equal to the length
. Neither does the observation of a coincidence, that is, of the simultaneous presence of two objects at the same point of space, entail any knowledge of a measure of duration. Hence, although we know nothing of the measurement of time, we cannot escape the conclusion that the two bodies have taken the same time to pass from
to
