And so, he attempts to defend this position, justify it to his disciples who are worried that it may not be true.

所以,他试图捍卫他的观点,并试图说服,那些怀疑这一点的学生们

耶鲁公开课 - 死亡课程节选

But there is one thing, Descartes concluded, that he cannot doubt, and the answer is he cannot doubt that he is himself thinking.

但笛卡尔认为,有一点是他无法置疑的,那就是,他无法怀疑自我思考的存在

耶鲁公开课 - 心理学导论课程节选