Gu Yanwu
Some of the most important first generation of Qing thinkers were Ming loyalists, at least in their hearts, including Gu Yanwu, Huang Zongxi, and Fang Yizhi. Partly in reaction to the presumed laxity and excess of the late Ming, they turned to Kaozheng, or evidential learning, which emphasized careful textual study and critical thinking.