is described in _In Memoriam_,
xcv.

And all at once it seem'd at last
The living soul was flash'd on mine,
And mine in this was wound, and whirl'd
About empyreal heights of thought,
And came on that which is, and caught
The deep pulsations of the world.

And again in the conclusion of the _Holy Grail_--

Let visions of the night or of the day
Come, as they will; and many a time they come,
Until this earth he walks on seems not earth,
This light that strikes his eyeball is not light,
This air that strikes his forehead is not air
But vision--yea, his very hand and foot--
In moments when he feels he cannot die,
And knows himself no vision to himself,
Nor the high God a A vision, nor that One
Who rose again.

"These three lines," said Tennyson, speaking of the last three quoted,
"are the (spiritually) central lines in the Idylls." They are also the
central lines in his own philosophy, for it was the experience of this
"vision" that inspired all his deepest convictions with regard to the
unity of all things, the reality of the unseen, and the persistence of
life.

The belief in the impotence of intellectual knowledge is very closely
connected, it is indeed based, upon these "gleams" of ecstasy. The
prologue to _In Memoriam_ (written when the poem was completed) seems to
sum up his faith after many years of struggle and doubt; but it is in
the most philosophical as well as one of the latest, of his poems, _The
Ancient Sage_, that we find this attitude most fully expressed. Tennyson
wrote of it: "The whole poem is very personal. The passages about
'Faith' and 'the Passion of the Past' were more especially my own
personal feelings." Through the mouth of the Sage, the poet declares in
impassioned words the position of the mystic, and points out the
impotence of sense-knowledge in dealing with that which is beyond either
the senses or the reason:

For Knowledge is the swallow on the lake
That sees and stirs the surface-shadow there
But never yet hath dipt into the abysm.

Tennyson, like Wordsworth, emphasises the truth that the only way in
which man can gain real knowledge and hear the "Nameless" is by diving
or sinking into the centre of his own being. There is a great deal of
Eastern philosophy and mysticism in the _Ancient Sage_, as, for
instance, the feeling of the unity of all existence to the point of
merging the personality into th