After Bruno's death, during the first half of the seventeenth century, Descartes seemed about to take the leadership of human thoughtbut his constant dread of persecution, both from Catholics and Protestants, led him steadily to veil his thoughts and even to suppress them. The execution of Bruno had occurred in his childhood, and in the midst of his career he had watched the Galileo struggle in all its stages.Since Roger Bacon, perhaps, no great thinker had been so completely abased and thwarted by theological oppression.
René Descartes