  The problem then is given human beings great capacity for self-deceit, how can it be prevented? Is not the attempt to prevent self-deceit as prone to self-deceit as anything else? Butler’s answer is that habitual and systematic self-reflection and self-governance by rigid rules are the best response. In a manner reminiscent of Epictetus’ famous maxim one must watch oneself as an enemy lying in ambush, and view one’s actions as an enemy would judging them harshly, Butler suggests a two part rule to this end “One is, to substitute another for yourself, when you take a survey of any part of your behavior, or consider what is proper and fit and reasonable for you to do on any occasion: the other part is, that you… consider yourself as the person affected by such a behavior,” (Sermon X §15). The rule “itself may be dishonestly applied” but even the misguided attempt to apply it may reveal more truth than not applying it at all. In the Analogy Butler argued that one of the central moral purposes of this life is as a probationary period in the acquisition of habits of self-governance (Analogy V). That these habits are not fool-proof is a consequence of the fact that our ability to apply them seriously to ourselves is one of the bases for our ultimate punishment and reward.