Answer:
Andre Breton is expressing his admiration for imagination.
Step-by-step explanation:
During the past few centuries, writers and artists in general tended to express the power of reason and its ability of thinking. Starting from the Renaissance, man is enthusiastic with the human brain. In the 18th century the rationality gets its crown and in 19th century writers thought that everything can be explained just by determining the causes of ongoings.
That changes in 20th century and Breton wants to explain that there is much more than just the reason and rational way of thinking, that there is imagination and the subconscious, and that we should try to seize it for being able to understand more of ourselves.