Final answer:
Joseph II of Austria enacted reforms such as religious tolerance and the abolition of serfdom, aligning closely with Enlightenment ideals, which Frederick II of Prussia and Catherine the Great of Russia did not fully embrace in their policies.
Step-by-step explanation:
Joseph II of Austria distinguished himself from other enlightened despots like Frederick II of Prussia and Catherine the Great of Russia by instituting radical reforms that included religious tolerance and the abolition of serfdom. Frederick II, while an admirer of enlightenment philosophies and a patron to philosophers like Voltaire, did not make such sweeping reforms pertaining to personal freedoms and rights. Catherine the Great, though she corresponded with Voltaire and Diderot and considered many enlightenment ideas, also stopped short of substantial social reform, largely retaining the serfdom system and privileging the nobility.
Joseph II's actions reflect a deeper commitment to enlightened thought and behavior, moving beyond the patronage and theoretical discussions of Frederick II and Catherine to implement policies that had a profound impact on the lives of his subjects. Joseph II's reforms were in line with the philosophical ideas of the Enlightenment, which sought to apply reason and scientific principles to every aspect of social life, including government and human rights – a contrast to the principles of divine-right absolutism that prevailed at the time.