How time the term avant-garde in the

How useful is the term'avant-garde' in explaining the development of art in Europe between 1900-1939?
Between 1900-1939 there were many different movements in art mainly due to two reasons, modernisation and the First World War.
The term'avant-garde' does not have one single meaning and has become synonymous with the evolving modern movement of art. 'Although'art for art's sake' is a term not often used positively today this modernist sense of the avant-garde relates to that tradition insofar as art is not seen to require any external justification – ethical or political – for it's products' . However looking at the term in historical context the term has a different provenance. The term was used for thefirst time in the 1830's not in a debate concerning art but in the'early socialist tradition as left-wing intellectuals and politicians tried to think through concepts of progress and freedom in emerging modern societies' . In his book'Opinions litteraires, philosophiques et industrielles' Henri de Saint Simon the French Utopian Socialist philosopher used for thefirst time the term avant-garde in the relation to art. Saint-Simon constructed an imaginary debate between an artist, a savant (a scie!
ntific or technical intellectual) and an industrialist. The artist proposes that he, the savant and the industrialist should join forces and ensure social progress rather than relying on ruling classes to exercise leadership in society.
'We, the artists, will serve as the avant-garde: for amongst all the arms at our disposal, the power of the Arts is the swiftest and most expeditious. When we wish to spread new ideas amongst men, we use, in turn, the lyre, ode or song, story or novel; we inscribe those ideas on marble or canvas, and we popularise them in poetry them in poetry and in song…. If today our role seems limited or…