Query: What famous philosopher did Ibn Sina criticize heavily?
Context: Of linguistic significance even to this day are a few books that he wrote in nearly pure Persian language (particularly the Danishnamah-yi 'Ala', Philosophy for Ala' ad-Dawla'). Ibn Sīnā's commentaries on Aristotle often criticized the philosopher,[citation needed] encouraging a lively debate in the spirit of ijtihad.