of change whatever, take the twenty seconds themselves
elapsing. If time be infinitely divisible, and
it must be so on intellectualist principles, they
simply cannot elapse, their end cannot be reached;
for no matter how much of them has already elapsed,
before the remainder, however minute, can have wholly
elapsed, the earlier half of it must first have elapsed.
And this ever re-arising need of making the earlier
half elapse
first leaves time with always something
to do
before the last thing is done, so that
the last thing never gets done. Expressed in
bare numbers, it is like the convergent series 1/2
plus 1/4 plus 1/8..., of which the limit is one.
But this limit, simply because it is a limit, stands
outside the series, the value of which approaches
it indefinitely but never touches it. If in the
natural world there were no other way of getting things
save by such successive addition of their logically
involved fractions, no complete units or whole things
would ever come into being, for the fractions’
sum would always leave a remainder. But in point
of fact nature doesn’t make eggs by making first
half an egg, then a quarter, then an eighth,
etc.,
and adding them together. She either makes a
whole egg at once or none at all, and so of all her
other units. It is only in the sphere of change,
then, where one phase of a thing must needs come into
being before another phase can come that Zeno’s
paradox gives trouble.
And it gives trouble then only if the succession of
steps of change be infinitely divisible. If a
bottle had to be emptied by an infinite number of
successive decrements, it is mathematically impossible
that the emptying should ever positively terminate.
In point of fact, however, bottles and coffee-pots
empty themselves by a finite number of decrements,
each of definite amount. Either a whole drop emerges
or nothing emerges from the spout. If all change
went thus drop-wise, so to speak, if real time sprouted
or grew by units of duration of determinate amount,
just as our perceptions of it grow by pulses, there
would be no zenonian paradoxes or kantian antinomies
to trouble us. All our sensible experiences,
as we get them immediately, do thus change by discrete
pulses of perception, each of which keeps us saying
‘more, more, more,’ or ‘less, less,
less,’ as the definite increments or diminutions
make themselves felt. The discreteness is still
more obvious when, instead of old things changing,
they cease, or when altogether new things come.
Fechner’s term of the ‘threshold,’
which has played such a part in the psychology of
perception, is only one way of naming the quantitative
discreteness in the change of all our sensible experiences.
They come to us in drops. Time itself comes in
drops.