I couldn’t find a formal manifesto by Pablo Picasso and George Braque but I found these artist statements:
“Cubism is not a reality you can take in your hand. It’s more like a perfume, in front of you, behind you, to the sides, the scent is everywhere but you don’t quite know where it comes from” Picasso.
“The goal I proposed when making cubism? To paint and nothing more…with a method linked only to my thought…Neither the good nor the true; neither the useful nor the useless.” Picasso.
“What greatly attracted me – and it was the main line of advance of Cubism – was to give material expression to this new space of which I had an inkling. So I began to paint chiefly still lifes, because in nature there is a tactile, I would almost say a manual space…that was the earliest Cubist painting – the quest for space.” George Braque.
“If I have called Cubism a new order, it is without any revolutionary ideas or any reactionary ideas…One cannot escape from one’s own epoch, however revolutionary one may be.” George Braque.
Picasso and Braque abandoned the use of perspective and turned away from the realistic modelling of figures.
The first phase of Cubism became known as Analytic Cubism, exploring open form, piercing figures and objects by letting the space flow through them, blending background into foreground and showing objects from various angels.
The second phase was known as Synthetic Cubism because these artists explored the use on non-art materials as abstract signs.