It is a mistake for a sculptor or a painter to speak or write very often about his job. It releases tension needed for his work. But trying to express his aims with rounded-off logical exactness, he can easily become a theorist whose actual work is only a caged-in exposition of conceptions evolved in terms of logic and words. But though the non-logical, instinctive, subconscious part of the mind must play its part in his work, he also has a conscious mind which is not inactive. The artist works with a concentration of his whole personality, and the conscious part of it resolves conflicts, organizes memories, and prevents him from trying to walk in two directions at the same time.
It is likely, then, that a sculptor can give, from his own conscious experience, clues which will help others in their approach to sculpture.
Henry Moore: The Sculptor Speaks, in "The Listener" London 1937

culpture, for me, must have life in it, vitality. It must have a feeling for organic form, a certain pathos and warmth. Purely abstract sculpture seems to me to be an activity that would be better fulfilled in another art, such as architecture. That is why I have never been tempted to remain a purely abstract sculptor. Abstract sculptures are too often but models for monuments that are never carried out, and the works of many abstract or 'constructivist' sculptors suffer from this frustration in that the artist never gets around to finding the real material solution to his problems. But sculpture is different from architecture. It creates organisms that must be complete in themselves. An architect has to deal with practical considerations, such as comfort costs and so on, which remain alien to an artist, very real problems that are different from those which a sculptor has to face [...] A sculpture must have its own life. Rather than give the impression of a smaller object carved out of a bigger block, it should make the observer feel that what he is seeing contains within itself its own organic energy thrusting outwards – if a work of sculpture has its own life and form, it will be alive and expansive, seeming larger than the stone or wood from which it is carved. It should always give the impression, whether carved or modeled, of having grown organically, created by pressure from within.
Edouard Roditi, Dialogues on Art, Secker and Warburg, London 1960

he average man, who's got very little time to look at sculpture and painting, looking at sculpture such as mine, would find such work puzzling and strange. I think this is natural because for over twenty years I, like most artists, have been thinking all day long about sculpture and painting, and if after all that I can only produce something which the average man, who has very little time to think about it, would immediately recognize as something he would have done if he'd had the technical experience, then I think that my time would not have been very profitably spent. I think that is true of the past too, and that all good art demands an effort from the observer and he should demand that it extends his experiences of life. Art and Life, The living Image, in 'The Listener', Vol. XXVI, No. 670, London 1941
Flintstones, pebbles, shells and driftwood have all helped me to start off ideas, but far more important to me has been the human figure and its inner skeleton structure. You can feel that a bone has had some sort of use in its life; it has experienced tensions, has supported weights and has actually performed an organic function, which a pebble has not done at all. In themselves pebbles are dead forms, their shape is accidental, and merely to copy them would not in itself create a sculptural form. It is what I see in them that gives them their significance.
John Hedgecoe, Henry Moore, Henry Moore, Nelson, London 1968

culpture should always at first sight have some obscurities, and further meanings. People should want to go on looking and thinking; it should never tell all about itself immediately. Initially both sculpture and painting must need effort to be fully appreciated, or else it is just an empty immediacy like a poster, which is designed to be read by the people on top of a bus in half a second. In fact all art should have some more mystery and meaning to it than is apparent to a quick observer. In my sculpture, explanations often come afterwards. I do not make a sculpture to a program or because I have a particular idea I am trying to express. While working, I change parts because I do not like them in such a way that I hope I am going to like them better. The kind of alteration I make is not thought out; I do not say to myself - this is too big, or too small. I just look at it and, if I do not like it I change it. I work from likes and dislikes, and not by literary logic. Not by words, but by being satisfied with form. Afterwards I can explain or find reasons for it, but that is rationalization after the event. I can look at old sculptures and find meanings in them and explanations which at the time were not in my mind at all - not consciously anyway.
John Hedgecoe, Henry Moore
, Henry Moore, Nelson, London 1978