Poincaré on Choosing Facts to Focus On
From The Hunt for Vulcan:
Observations are essential; but, as Le Verrier argued through his analysis of the minor planets, they are not in themselves sufficient. The scientists's duty confronting some new circumstances is to find the meaning within the flood of new data. Half a centruy later, his compatriot the great mathematician Henri Poincaré would put it like this: "We can not know all facts and it is necessary to choose those which are worthy of being known."