There is a use of [the concept] “infinity” which is valid, as Aristotle
observed, and that is the mathematical use. It is valid only when used to
indicate a potentiality, never an actuality. Take the number series as an
example. You can say it is infinite in the sense that, no matter how many
numbers you count, there is always another number. You can always keep on
counting; there’s no end. In that sense it is infinite — as a potential. But
notice that, actually, however many numbers you count, wherever you stop, you
only reached that point, you only got so far. . . . That’s Aristotle’s point
that the actual is always finite. Infinity exists only in the form of the
ability of certain series to be extended indefinitely; but however much they
are extended, in actual fact, wherever you stop it is finite.