‘Every piece of philosophical writing is primarily addressed by the writer to himself. Its purpose is not to select from among his thoughts those of which he is certain and to express those, but the very opposite: to fasten upon the difficulties and obscurities in which he finds himself involved, and try, if not to solve or remove them, at least to understand them better … The philosophers who have had the deepest instinct for style have repeatedly shrunk from adopting the form of a lecture or instructive address, and chosen instead that of a dialogue … or a meditation … or a dialectical process where the initial position is modified again and again as difficulties in it come to light. The prose-writer’s art is an art that must conceal itself and produce not a jewel that is looked at for its own beauty but a crystal in whose depth the thought can be seen without distortion or confusion; and the philosophical writer in especial follows the trade not of a jeweller but of a lens-grinder. He must never use metaphors or imagery in such a way that they attract to themselves the attention due to his thought; if he does that, he is writing not prose but, whether well or ill, poetry; but he must avoid this not by rejecting all use of metaphors and imagery, but by using them, poetic things themselves, in the domestication of prose: using them just so far as to reveal thought, and no further’.
– R.G. Collingwood, An Essay on Philosophical Method (ed. James Connelly and Giuseppina D’Oro; Oxford: Oxford University Press, 2008), 209–214.