Bad faith is commonly conceived as lying to oneself or self-deception. This folk definition is too simplistic as it undermines the rich ontological underpinnings of bad faith. While both simple self-deception and bad faith are opposed to the general phenomenon of lying (to others), for Sartre bad faith is also meant to explain both the working of consciousness and the ubiquity of pre-judicative nothingness. Together, consciousness and nothingness supply the special ontological foundation required for bad faith to operate. To enter into bad faith is to escape from the anguish of the experience of insubstantiality and freedom into deterministic attitudes about the self, such as the deceiver/deceived bipolarity of Freudian psychoanalysis. Sartre rejects the thesis that there can be hidden motivations in consciousness by arguing for the reflexivity and the translucency of consciousness. Further, he would take the ubiquity of nothingness to explain the wide prevalence of bad faith as a state-of-being in the world. Bad faith cannot be equated with simple cases of self-deception as bad faith is sustained by a unique mix of ontological postulates. Sartre argues for this point cogently through his examples of bad faith in Being and Nothingness. In these examples, Sartre shows that sincerity, the purported anti-thesis of self-deception, causes one to fall even deeper into bad faith.

恶意通常被认为是对自己撒谎或自欺欺人。这种民间定义太简单了，因为它破坏了恶意的丰富本体论基础。尽管简单的自我欺骗和恶意都与撒谎（对他人）的普遍现象相对，但对于萨特来说，恶意也意在解释意识的作用和审判前虚无的普遍存在。意识和虚无共同提供了特殊的本体论基础恶意操作所必需。陷入恶意是从摆脱无实体和自由的经历的痛苦中摆脱出对自我的确定性态度，例如对弗洛伊德精神分析的欺骗者/欺骗者的两极分化。萨特拒绝了关于意识的自反性和半透明性的论点，即意识中可能存在隐藏的动机。此外，他会以虚无的普遍性来解释恶意作为世界上一种生存状态的广泛流行。恶意不能与简单的自欺欺人相提并论，因为恶意是由本体论假设的独特组合所维持的。萨特通过他对存在与虚无的不良信念的实例来有力地论证了这一点。。在这些例子中，萨特证明了所谓的自欺欺人的诚意是诚意，会使人陷入更深的恶意。