Islamic jihadists want to destroy the artifacts of non-Muslim civilizations, because doing so testifies to the truth of Islam, as the Qur’an suggests that the destroyed remnants of ancient non-Muslim civilizations are a sign of Allah’s punishment of those who rejected his truth: Many were the Ways of Life that have passed away before you: travel through the earth, and see what was the end of those who rejected Truth. (Qur’an 3:137) This is one of the foundations of the Islamic idea that pre-Islamic civilizations, and non-Islamic civilizations, are all jahiliyya — the society of unbelievers, which is worthless. Obviously...