is that good and evil are purely relative terms (see _The
Bean-stripe_), and that one cannot exist without the other. It is evil
which alone makes possible some of the divinest qualities in
man--compassion, pity, forgiveness patience. We have seen that Shelley
shares this view, "for none knew good from evil"; and Blake expresses
himself very strongly about it, and complains that Plato "knew nothing
but the virtues and vices, the good and evil.... There is nothing in all
that.... Everything is good in God's eyes." Mysticism is always a
reconcilement of opposites; and this, as we have seen in connection with
science and religion, knowledge and love, is a dominant note of
Browning's philosophy. He brings it out most startlingly perhaps in _The
Statue and the Bust_, where he shows that in his very capacity for
vice, a man proves his capacity for virtue, and that a failure of energy
in the one implies a corresponding failure of energy in the other.

At the same time, clear knowledge that evil is illusion would defeat its
own end and paralyse all moral effort, for evil only exists for the
development of good in us.

Type needs antitype:
As night needs day, as shine needs shade, so good
Needs evil: how were pity understood
Unless by pain?

This is one reason why Browning never shrank from the evil in the world,
why indeed he expended so much of his mind and art on the analysis and
dissection of every kind of evil, laying bare for us the working of the
mind of the criminal, the hypocrite, the weakling, and the cynic;
because he held that--

Only by looking low, ere looking high
Comes penetration of the mystery.

There are other ways in which Browning's thought is especially mystical,
as, for instance, his belief in pre-existence, and his theory of
knowledge, for he, like Plato, believes in the light within the soul,
and holds that--

To know
Rather consists in opening out a way
Whence the imprisoned splendour may escape,
Than in effecting entry for a light
Supposed to be without.

_Paracelsus_, Act I.

But the one thought which is ever constant with him, and is peculiarly
helpful to the practical man, is his recognition of the value of
limitation in all our energies, and the stress he lays on the fact that
only by virtue of this limitation can we grow. We should be paralysed
else. It is Goethe's doctrine of _Entbehrung_, and it is