Shelley does not commit himself to definite pantheism anywhere. But there are passages which seem to come near to pantheism. He often conceives of a Spirit diffused through, and permeating the universe — a Spirit that seems also to impel human thoughts. Shelley pays homage to such a Spirit in his Hymn to Intellectual Beauty. It is a spirit that links the very grass we tread under feet with the tremulous stars in the heavens. It, as Shelley says, is reflected in light and colour, in life and motion, which fill every crack and cranny in the universe. Sometimes it stirs the very air and weaves a spell of radiance. Shelley does often experience it in a thrill of thought. Shelley often describes such moments of rapt vision. One passage may be quoted here:
“How calm it was! the silence there
By such a chain was bound
That even the busy woodpecker
Made stiller by her sound
The invisible quietness;
The breath of peace we drew
With its soft motion made not less
The calm that round us grew.
There seemed from the remotest seat
Of the white mountain waste,
To the soft flower beneath our feet,
A magic circle traced,—
A spirit interfused around,
A thrilling silent life.
To momentary peace it bound
Our mortal nature's strife.” —To Jane: The Recollection.
We have the most definite exposition of his pantheistic views in Adonais. We quote the following as an illustration:
“He is a portion of the loveliness
Which once he made more lovely. He doth bear
His part, while the One Spirit's plastic stress
Sweeps through the dull dense world; compelling there
All new succession to the forms they wear
Torturing th’ unwilling dross, that checks its flight,
To its own likeness, as each mass may bear;
And bursting in its beauty and its might
From trees and beasts and men into the heaven's light.”
The One Spirit is the Universal Mind, working in and through nature, into which are infused life and motion, which is shaped into form and colour and invested with beauty and splendour and as Shelley says here, a poet also bears his part in making the world beautiful. Nature is also a manifestation of the Universal Mind. Pantheism makes Nature and God almost identical. It is the idea of a spiritual principle ruling and pervading the observable world.
Stopford Brooke writes, “Shelley was not an atheist or a materialist. If he may be said to have occupied any theoretical position, it was that of an Ideal Pantheist: the position, which with regard to Nature a modern Port who cares for the subject, naturally whatever may be his personal view, adopts in the realm of art. Wordsworth, a plain Christian at home, wrote about Nature as a pantheist. The artist, as I said, loves to conceive of the universe, not as dead, but as alive. Into that belief Shelley, in hours of inspiration, continually rose and his work is seldom more impassioned and beautiful than in the passages where he feels and believes in this manner. The finest example is towards the close of the Adonais. In his mind however, the living spirit which, in its living, made the Universe, was not conceived of a Thought, as Wordsworth conceived it, but as Love operating into Beauty; and there is a passage on this idea in the fragment of the Coliesum which is as beautiful in prose as that of Adonais is in verse. But it is only in higher poetic hours that Shelley seems or cares to realise this belief. In the quieter realms of poetry, in daily life, he confessed no such creed plainly; he had little or no belief in a thinking or loving existence behind the phenomenal universe. It is infinitely improbable, he says, that cause of the mind is similar to mind. Nothing can be more characteristic of him - and he has the same temper in other matters - than that he should have a faith with regard to a Source of Nature, into which he could soar when he pleased, in which he could live for a time, but which he did not choose to live in, to define, or to realise, continually.”
However, Santayana in his work The Winds of Doctrine feels that the philosophy expressed by Shelley in his nature poems like Adonais is not “Pantheism” but “panpsychism”. Panpsychism believes that all nature has a psychic (or spiritual) side. Shelley also shows that Nature has an all - pervading Spirit.