It is an irony that because Moore's figures are so instantly recognisable their form has hidden the fact that they have both historical context and often surprising content. For example, when you consider that Moore was one of only 52 men from his battalion of 400 (he was the youngest soldier in it) to survive the Battle of Cambrai in 1917, his experiments with the human form take on a different aspect. He himself claimed: "For me, the war passed in a romantic haze of trying to be a hero" — but the sculptures show bodies taken apart, reshaped and rearranged in a way that uncomfortably mirrors what he had seen shells and bullets do to his comrades. And the megaliths of his later career can be reread not as extensions of an ancient landscape but as giant bones, the parts of a buried ossuary showing through the soil.

It is worth remembering too that Moore was one of the organisers of the 1936 International Surrealist Exhibition in London. He was, therefore, familiar not just with Surrealist imagery but also with the psychological and sexual theories that underpinned it. Seen in that light, his experiments with sculptural holes and concavities seem less to do with mass and three-dimensionality and instead rife with sexual symbolism. If you put any one of his extruded reclining figures into a painting by, say, Dalí, it would fit perfectly, not just for their dreamlike shapes but for their naked sexual invitation.

The psychological aspect is apparent too even in the most simple-seeming group of his works — his seated women and mother and child series. These may indeed be expressions of his inherent humanism but they are also obviously Freudian motifs, deeply personal and linked with the death of his mother in 1943 and the birth of his only child, Mary, in 1946. He explicitly identified his 1957 Seated Woman with his mother, describing how in modelling it he was "unconsciously giving to its back the long-forgotten shape of the one I had so often rubbed as a boy". At this point, most psychoanalysts would be scribbling the words "Oedipus complex" in their notepads.

Moore once said that "there are universal shapes to which everyone is subconsciously conditioned and to which they can respond, if their conscious control does not shut them off" — a claim that is both a statement of his aims as an artist and a recasting of Jung's idea of the "collective unconscious". It would be a mistake though to see Moore only through the murky spectacles of psychology. He was too quintessentially concerned with aesthetics for that. However, what this exhibition makes vividly clear is that the real reason it is wrong to dismiss him as simply a humanist schooled in the language of nature is because for the bulk of his life he was at the mercy of a host of covert and often dark impulses too.