Almost all works by Shelley show his restless spirit, his refusal of social conventions, political oppression and any form of tyranny, and his faith in a better future. Less disciplined and methodical than Wordsworth or Coleridge, he remains nevertheless a poet of great conviction and powerful musicality, and the author of some of the finest lyrical poetry in English literature. Shelley believed strongly in the principles of freedom and love, which he regarded as remedies for shortcomings and evils of society. Through love he believed man could overcome any political, moral and social conventions.
Love and freedom are the key notes of his character and consequently of his poetry. He believed that any type of institution (for example church or state) led to superstition and selfishness, and that man can express his utmost capabilities only if he is free from external retrains. Yet freedom was not to be licence. There must be lows but there must be love, too, the love which is the principle of all actions, the force that moves both the physical universe and the inner world of the spirit. Only through love will the world be improved.
Shelley's rejection of conventional modes of thinking led to a ceaseless search for new ideals, and embraced the theory of Godwin and neo-Plato. He partly altered Godwin's theories, whose materialism become a hope in the moral freedom and of man and a religious pantheism, and whose anarchical egoism was turned into a humanitarian brotherhood. From Plato he derive his mystical and intellectual belief in a society ruled by ethics and wisdom; moreover, he absorbed the idea of reality as an illusionary image of the true reality of eternity, and of an idealistic pantheism. Indeed, like Plato, he maintained that matter does not exist and the only reality his the spirit and that nature is as alive as man and, like him, is endowed with a soul. Each idea derives from the idea of Good, which is the source of all things. The life we live here is like a veil which strains true reality. At the same time, however, S. believed that man, tied to this life on earth, has the power to attain moral perfection, so as to reunite himself with the pure source which he come from.
From his early atheism he came to a firm belief in a universal spiritual force, on which man is a part: man may change, decay and die, but his spirit will join the eternal Spirit of the Universe, which continually creates new life. His religion was therefore pantheistic, which for him was not an aesthetic conception of the universe (as Wordsworth) or philosophical doctrine (as for Coleridge), but an actual true faith.
His pantheism obviously involved Nature, which sympathizes with man, and is for him an eternal source of joy and happiness. Like W., S saw nature permeated by the great spiritual force which animates everything, but, unlike W., he found no message for man in it, but only pleasure. Indeed, nature represents the favourite refuge from the disappointed and injustice of the ordinary world and the interlocutor of his melancholy dreams and of his hopes for a better future. Moreover, while W.'s inspiration was never originated by direct sensation, but by recollection on it, S's was immediate. Ecstasy was in fact the product of direct perception, which he considered superior even to thought and feeling. It was indeed a kind of sensation in a pure state, so deep and intense as to perceive even the most immaterial aspect of nature. Perception alone, therefore, could lead to total reciprocity and identification between man and nature.