Beauty: I wholly deny that that the impressions of beauty are in any way sensual ; they are neither sensual nor intellectual, but moral. (MP, Vol 1, Chapter 2).
(... ) it is evident that the sensation of beauty is not sensual on the one hand, nor is it intellectual on the other ; but is dependent on a pure, right, and open state of the heart. (Ibid, 40).
(...) By the term Beauty, then, properly are signified two things. First, that external quality of bodies already so often spoken of, and which, whether it occur in a stone, flower, beast, or man, is absolutely identical: which, as I have already asserted, may be shown to be in some sort typical of the Divine attributes, and which, therefore, I shall, for distinction’s sake, call Typical Beauty. (MP Vol. 1).
(...) man cannot advance in the invention of beauty, without directly imitating natural form. (SL, Lamp of Beauty).
(...) Must not beauty, then, it will be asked be sought for in the forms which we associate with our every-day life ? (SL, Lamp of Life).
(...) The essential characters of Beauty depended on the expression of vital energy in organic things... (SL, Lamp of Life).
(...) These sources of beauty, however, are not presented by any very great work of art in a form of pure transcript. They invariably receive the reflection of the mind under whose influence they have passed, and are modified or coloured by its image. This modification is the work of Imagination. (MP, Vol. 2, para. 1).
Vital Beauty: (...) the appearance of felicitous fulfillment of function in living things, more especially of the joyful and right exertion of perfect life in man ; and this kind of beauty I shall call Vital Beauty. (MP, Vol. 1, para. 16).
(...) the first state of vital beauty is defined to be Happiness, perceived with sympathy ; the second, ... Moral intention, perceived with praise. Hence the first aphorism of the Laws of Fesole: "All great art is prune." (MP, Vol. 1, Chapter 1).
(...) We think we love it (art) for its beauty, but really we love it for its vitality. (SV, Intro.).
Of truth and beauty: (...) that is to say, truth first, and beauty afterwards. High art differs from low art in possessing an excess of beauty in addition to its truth, not in possessing an excess of beauty inconsistent with truth. (MP, para. 34).
Enjoyment: (...) I believe the right question to ask, respecting all ornament, is simply this: Was it done with enjoyment—was the carver happy while he was about it? It may be the hardest work possible, and the harder because so much pleasure was taken in it; but it must have been happy too, or it will not be living. (MP, Chapter 5, para. 24).
Nature: Great art accepts Nature as she is, but directs the eyes and thoughts to what is most perfect in her; false art saves itself the trouble of direction by removing or altering whatever it thinks objectionable. (MP, Vol. 2, Chapter 3, para.13).
(...) The more a painter accepts nature as he finds it, the more unexpected beauty he discovers in what he at first despised (Ibid.)
(...) High art, therefore, consists neither in altering, nor in improving nature (Ibid.)
Nature ... keeps whatever she has done best, close sealed, until it is regarded with reverence (Ibid).
(...) He who is closest to Nature is best. (Ibid, Chapter 10, para. 5).
take pleasure at last in every aspect of age and desolation which emancipates the objects of nature from the government of men. (Ibid, Chapter 16, para. 5).
(...) Observe: the whole force of education, until very lately, has been directed in every possible way to the destruction of the love of nature. (Ibid, Chapter 17, para. 31).
(...) Instead of supposing the love of nature necessarily connected with the faithlessness of the age, I believe it is connected properly with the benevolence and liberty of the age. (Ibid, Chapter 17, para. 34).
Ruskin's aesthetics: (...) For as (1) the choice of the high subject involves all conditions of right moral choicer and as (2) the love of beauty involves all conditions of right admiration, and as (3) the grasp of truth involves all strength of sense, evenness of judgment, and honesty of purpose, and as (4) the poetical power involves all swiftness of invention, and accuracy of historical memory, the sum of all these powers is the sum of the human soul. (MP, para. 42).
Rules: (...) The great men ... have no rules; cannot comprehend the nature of rules;—do not, usually, even know, in what they do, what is best or what is worst: to them it is all the same; something they cannot help saying or doing,—one piece of it as good as another, and none of it (it seems to them) worth much. The moment any man begins to talk about rules, in whatsoever art, you may know him for a second-rate man; and, if he talks about them much, he is a third-rate, or not an artist at all. To this rule there is no exception in any art. (MP, Vol. 3, para. 84).
Style: (...) The style is greater or less in exact proportion to the nobleness of the interests and passions involved in the subject. (MP, Vol. 3, para. 5).
Truth: (...) There is never vulgarity in a whole truth, however commonplace. It may be unimportant or painful. It cannot be vulgar. Vulgarity is only in concealment of truth, or in affectation. (MP, Vol. 3, para. 83).
(...) Every duty which we omit obscures some truth which we should have known; and the guilt of a life spent in the pursuit of pleasure is twofold, partly consisting in the perversion of action, and partly in the dissemination of falsehood. (SV, Chapter 3, para. 28).
(...) so far as the truth is seen by the imagination in its wholeness and quietness, the vision is sublime. (SV, Idem, para. 62).
Loving enthusiasm: (...) this loving enthusiasm, which seeks for a beauty fit to be the object of eternal love; this inventive skill, which kindly displays what exists around us in the world; and this playful energy of thought which delights in various conditions of the impossible (MP, Vol. 3, 71).
Ugly: I would fain be allowed to assume also the converse of this, namely, that forms which are not taken from natural objects must be ugly. (SL, Chapter 4)
List of works by Ruskin cited here
SV: The Stones of Venice, in 3 Volumes, by Project Gutenberg. Vol. 1, Vol. 2, Vol. 3.
MP: Modern Painters, in 5 Volumes, by Project Gutenberg. Vol. 1, Vol. 2, Vol. 3, Vol. 4, Vol. 5.
SL: The Seven Lamps of Architecture, by Project Gutenberg,