And although, in the _Progress of the Soul_, he failed to give
expression to it, yet his belief in progress is unquenchable. He fully
shares the mystic's view that "man, to get towards Him that's Infinite,
must first be great" (_Letter to the Countess of Salisbury_).

In his treatment of love, Donne's mystical attitude is most clearly
seen. He holds the Platonic conception, that love concerns the soul
only, and is independent of the body, or bodily presence; and he is the
poet, who, at his best, expresses this idea in the most dignified and
refined way. The reader feels not only that Donne believes it, but that
he has in some measure experienced it; whereas with his imitators it
degenerated into little more than a fashionable "conceit." The
_Undertaking_ expresses the discovery he has made of this higher and
deeper kind of love; and in the _Ecstasy_ he describes the union of the
souls of two lovers in language which proves his familiarity with the
description of ecstasy given by Plotinus (_Enn._ vi. 9, § 11). The great
value of this spiritual love is that it is unaffected by time and space,
a belief which is nowhere more exquisitely expressed than in the refrain
of his little song, _Soul's Joy_.[29]

O give no way to griefe,
But let beliefe
Of mutuall love,
This wonder to the vulgar prove
Our Bodyes, not wee move.

In one of his verse letters to the Countess of Huntingdon[30] he
explains how true love cannot be desire:

'Tis love, but with such fatall weaknesse made,