Shelley is a poet who often gives the impression that he is so entranced by the sound of his own words that the meaning of a poem is subordinated to that sound, or, to put it another way, the sound seems to create the meaning, not the other way around as one might expect. In "Mont Blanc," he builds a mountain of words that are a human analogue to the vastness of the scene before him. The words as a whole, and the sheer weight of them, are a symbol of the message that Shelley finally does convey explicitly at the close of the poem. But the thoughts projected by the speaker leading up to that conclusion arguably form a paradox. The scene Shelley describes is so huge, so unfathomable, that it can barely be comprehended by the human mind. It does not (unlike in Wordsworth) represent a positive force, but almost the opposite:

Yet not a city, but a flood of ruin
Is there, that from the boundaries of the sky
Rolls its perpetual stream . . . the race of man
Flies far in dread; his work and dwelling vanish,
Like smoke before the tempest's stream.

This is not benign nature, but a destructive power that is a kind of adversary to humanity.

If we extend the comparison with Wordsworth, the gulf between the first and second generations of Romantics becomes very obvious. Wordsworth struggles with his inner contrary forces but "finds strength in what remains behind" from the recollections of the past and his communion with the outer world, which began in childhood. His is an optimistic worldview, or at least an attempt at one. Shelley, like his closer contemporaries Byron and Keats, holds a more pessimistic view. He struggles too, fighting against the forces that bring humans down and dreaming (in the "Ode to the West Wind") that his lips will be the "trumpet of a prophecy" to "unawakened earth." Perhaps, in "Mont Blanc," this is the still sleeping earth being depicted—not merely as a realm of sleep but as one of death. The last section of the poem unites this concept of nature with Shelley's almost desperate wish to see something more than a harsh, eternal adversary in the outside world. He seems to be posing the old question of whether a tree that falls in the forest actually makes a sound if no one is there to hear it, but he does so in language much more elevated and multi-layered:

And what were thou, and earth, and stars, and sea,
If to the human mind's imaginings
Silence and solitude were vacancy?

This is the paradox inherent in the poem: despite the vastness of nature, the implication is that it's humans and their thoughts that give meaning to the external world. Rather than allowing himself to be crushed by the awesome sight before him, the speaker makes the final point that this vastness would be without significance in the absence of his reflections on it.

As opposed to William Wordsworth's "Lines Composed A Few Miles above Tintern Abbey" in which the poet compares his present adult experience of nature with the "haunted" passionate experience he had as a youth who "bounded o'er the mountains," Shelley's mind prevails in his discussion of nature and is both rational and creative. Moreover, for Shelley, it is the mind that provides nature its meaning: the mind lends itself and nature the "sublime" experience. For, in the final lines, Shelley asks,

And what were thou, and earth, and stars, and sea,
If to the human mind's imaginings
Silence and solitude were vacancy?