Philosophy, impatient as it may be to build, has much work yet remaining as pioneer* for the overgrowth of ages. It makes one step towards this object; it destroys error, and the roots of error. It leaves, what is too often the duty of the reformer in political and ethical questions to leave, a vacancy.# It reduces the mind to that freedom in which it would have acted, but for the misuse of words and signs, the instruments of its own creation. -- By signs, I would be understood in a wide sense, including what is properly meant by that term, and what I peculiarly mean. In this latter sense almost all familiar objects are signs, standing not for themselves but for others, in their capacity of suggesting one thought, which shall lead to a train of thoughts. -- Our whole life is thus an education of error. (Reiman-Powers, eds., Shelley's Poetry and Prose, p. 477)
#see 1.1.4, and note.