 In addition to thinking that there are some truths that are impervious to doubt, Malebranche also has a different understanding of Descartes’ principle that whatever one clearly and distinctly is true. Descartes maintains that when I clearly and distinctly perceive something my will is causally compelled to affirm it. So, for example, if I understand the proposition that five is the sum of two added to three then I will spontaneously affirm its truth. But as one commentator has noted, Malebranche has a normative, rather than a causal-psychological conception, of clear and distinct perceptions (Lennon 2000). Reason ‘obliges,’ rather than causally compels, my will to assent. Indeed, I can resist a clear and distinct perception, but only at the risk of ‘feeling an inward pain and the secret reproaches of reason’ (Search 1.2, OC 1:55; LO 10). This is significant because it explains why Malebranche refuses to take some forms of skepticism seriously: skepticism with respect to things perceived through clear and distinct perceptions is simply perverse, for it violates norms to which reason demands adherence (Lennon 2000, 19).