ABSOLUTE VS. RELATIONAL TIME
Newton states in the Scholium of his Principia, “Absolute, true, and mathematical time, of itself, and
from its own nature flows equablywithout regard to anything external, and byanother name is called
duration: relative, apparent, and common time, is some sensible and external (whether accurate or
unequable) measure of duration by the means of motion, which is commonly used instead of true
time; such as an hour, a day, a month, a year.” What does this mean? One thing it means is that time
would flow even if nothing else existed. That is, even in an empty universe, time would still pass.
The existence of time is independent of anything else; physical objects, observers, etc. Another is
that absolute time is not perceivable. Only common time effects can be observed, through the use
of clocks, etc., and entails motion, in some way.
Newton held an “Absolute” or “Substantival” view of both space and time. That is, he believed that
space and time exist independently of the presence of any material bodies or events. The contrary
view is “Relationalism”, the view that space and time are simply relations which hold between
independently existing material bodies or events. The source of the earliest and best debate on this
issue is the
, a series of letters exchanged between Leibniz and
Samuel Clarke, a disciple of Newton’s. It has long been speculated that Newton was at the veryleast
looking over Clarke’s shoulder as he wrote his replies to Leibniz, and perhaps even dictating them.
covers a broad range of topics, but much of it is on absolute vs. relational views
of space and time. Let’s look at some of the arguments. Keep in mind that these were written in the
last years of Leibniz’ life, which ended in 1716, and that he was attending at the royal court in
Hanover, serving the family that eventually came to rule England, supplying King George the I, II
and III, and keep in mind the religious sentiment that prevailed throughout Europe at thetime. It had
only been 75 years since Galileo was tried bythe Inquisition for supporting Copernicanism, and 115
years since Giordano Bruno was burned at the stake for suggesting that the universe was infinite and
that the stars were just distant versions of the Sun. Leibniz and Newton took turns accusing one
another of promulgating atheism in their philosophies, which in those days was a serious accusation.
The Baroque Cycle
, a trilogy by Neal Stephenson, for a (fictional, but in many ways accurate)
account of the conflict between Leibniz and Newton.
Clearly, Newton thought of time as a
, whose existence and nature depends upon
nothing external. So, for Newton, time could exist in the absence of change, a temporal metric could
exist in the absence of anyperiodic process, and temporal direction, or asymmetry, could exist in the
absence of the evolution of any physical system. The Relationalist would deny these, and maintain