For every Giordano Bruno burned at the stake, a thousand monks prudently refrained from exploring controversial issues, and a hundred thousand loyal Catholics remained fettered in an intellectual darkness so profound they could not even see their chains.
The cost of the Inquisition is not to be measured only in the smoking corpses of scholars and Jewish and Muslim people, or even those falsely accused of practicing Judaism, but in the lost memory of entire civilizations, and in the books that were never written. It is to be weighed by the end of Galileo's scientific career, in Descartes' cowardly refusal to publish his greatest work until after his death, and in his inability to learn from the criticisms that ensued. It is evident in the near absence of Iberian and Italian philosophers from the birth of physics, chemistry, and the calculus; even Lagrange left Italy in the end.
That today we fly through the air like birds; that we live in artificial mountains of glued-together stone; that we walk on the moon; that we use precious steel where our great-grandparents used wood; that only one in thirty children die before reaching adulthood, instead of one in five, as through all human history; that we routinely cure cancer; that I am writing you this note in letters of lightning playing over the surface of tiny stones from the other side of the world — these miracles are all thanks to the fact that the Inquisition did not reach England, or Prussia, or the Low Countries, except briefly. These miracles are thanks to the noble fruits of free inquiry.