Meditations - pg. 100

This is the chief and greatest perfection of man; so I think today's meditation has been of no small service, since I have been investigating the cause of error and falsehood. And surely no other cause is possible than the one I have explained. For whenever I restrain my will in making decisions, so that its range is confined to what the understanding shows it clearly and distinctly, I just cannot go wrong. For every clear and distinct perception is something; so it cannot come from nothingness, but must have God for its author; God, I say, the supremely Perfect, who it is absurd should be deceitful; therefore, it is indubitably true. Thus today I have learnt, not only what to avoid, so as not to be deceived, but also what to do,so as to attain the truth; I shall certainly attain it if only I take enough notice of all that I perfectly understand, and distinguish from this from everything else, which I apprehend more obscurely and confusedly. For the future I will take good care of this.