and time can be conceived independently of each other; but
their experiments to show it do not bear repetition.

All true contraries are universals. A universal concept is one of
"maximum extension," as logicians say, that is, it is without limit. The
logical limitation of such a universal is not its negation, but its
contrary, which is itself also a universal. The synthesis of the two can
be in theory only, yet yields a real product. To illustrate this by a
geometrical example, a straight line produced indefinitely is, logically
considered, a universal. Its antithesis or true contrary is not a
crooked line, as might be supposed, but the straight line which runs at
right angles to it. Their synthesis is not the line which bisects their
angle but that formed by these contraries continually uniting, that is,
the arc of a circle, the genesis of which is theoretically the union of
two such lines. Again, time can only be measured by space, space by
time; they are true universals and contraries; their synthesis is
_motion_, a conception which requires them both and is completed by
them. Or again, the philosophical extremes of downright materialism and
idealism are each wholly true, yet but half the truth. The insoluble
enigmas that either meets in standing alone are kindred to those which
puzzled the old philosophers in the sophisms relating to motion, as, for
instance, that as a body cannot move where it is and still less where it
is not, therefore it cannot move at all. Motion must recognise both time
and space to be comprehensible. As a true contrary constantly implies
the existence of its opposite, we cannot take a step in right reasoning
without a full recognition of both.

This relation of contraries to the higher conception which logically
must include them is one of the well-worn problems of the higher
metaphysics.

The proper explanation would seem to be, as suggested above, that the
synthesis of contraries is capable of formal expression only, but not of
interpretation. In pursuing the search for their union we pass into a
realm of thought not unlike that of the mathematician when he deals with
hypothetical quantities, those which can only be expressed in symbols--,
[square root] 1 for example,--but uses them to good purpose in reaching
real results. The law does not fail, but its operations can no longer be
expressed under material images. They are symbolic and for speculative
thought alone, though pregnant with