• This essay explores stoic ideas of good and evil by examining the meaning and ramifications of a definition of good and evil found in Epictetus, then expanding that definition gradually with the aid of other texts from Epictetus. Along the way, a challenge is presented to stoicism: if stoicism cannot explain why a serial killer's actions are evil, then stoicism will never be considered a viable moral system by decent human beings.
  
• In Discourse 29, Epictetus defines good and evil as follows. Each character produces good or evil depending on its opinions about externals, which are simply the materials and circumstances with which moral characters always interact. If we have correct opinions, we produce goodness in our interactions with externals. If we have incorrect opinions, we produce evil. We ourselves, via our moral character, are the source of good and evil. There is no other source.
  
• What makes our moral character good? The correctness of its opinions. And what makes an opinion correct? The stance it takes towards externals. Any opinion which attaches true positive or negative value to any external is incorrect, because externals have no true value. Opinions which treat externals as indifferents are correct. That is to say that opinions which treat indifferents as preferable, utterly indifferent, or dis-preferable, but not valuable in any way are correct.
  
• If this is all that Epictetus has to say about evil, it is woefully inadequate. Consider the following. There may be a stoic out there who notices the impulse within herself to kill cruelly and repeatedly and so goes about doing so when and where she can, all with the full understanding and enthusiastic agreement that it does not really matter whether she actually succeeds in killing (remember, stoics think that the mental disposition is more important than whether one's action succeeds in terms of externals). The act of trying and doing her best to inflict maximal pain and kill is what she values. When she succeeds externally, she notices how neatly it all came together as an enterprise and feels a joy in that, but still, she tries to analyze and learn from the experience how better to succeed in the future. When she fails externally, she analyzes the situation and either learns from it how better to proceed in the future or nonetheless feels the same joy as she felt at succeeding, because she notices how neatly it was all planned and how well the execution was attempted. She does notice the external factors which made the attempt fail or succeed, but they are externals and so do not matter to her sense of well-being and sense of accomplishment.
  
• The impulse to kill arises within her from wherever such impulses arise: it is not an artefact of her rational nature, but rather just something that occurs to her, as my taste for chocolate occurs to me. She is merely pursuing one of the many projects which pop into her mind in her life. Apparently, she qualifies as good under the stoic definition supplied above, because she is not valuing externals incorrectly and is taking her cues from her self.
  
• I suppose the stoic might respond to our stoic serial killer example as follows: what of it? You non-stoics are simply too limited. Life, death, and pain have no true value and the only reason you think that this stoic serial killer is evil is because you incorrectly attach value to externals. If that is all there is to the story, stoicism is unpalatable morally. I don't mean it's wrong: I cannot prove that, because once we grant the stoic's assumptions, the stoic's logic makes their argument valid. I simply mean that it is not to my taste, and in the end, perhaps that's all there is to morals: one must choose one's assumptions and then follow where they lead. But maybe there is more that the stoic might say in response.
  
• Later on in the same Discourse 29, Epictetus suggests that stealing a lamp has a cost: the thief had to be a thief to steal. Thievery makes one untrustworthy and "like a wild beast" (whatever that means). What is bad about being untrustworthy? Does it involve incorrect opinions about externals? Not necessarily. Thievery might be held to involve incorrect opinions about externals, such as that the thing stolen is actually of real value, but it does not necessarily do so. For a thief might do so stoically. Namely, he might steal with full awareness that he might not succeed and that successful thievery and the object of his theft is not truly valuable. He might even be doing it for the pure thrill of pulling off a virtuoso theft.
  
• So what of our murderous stoic? She will become untrustworthy too, and perhaps acquire a reputation for other inconvenient traits which might make murder more and more difficult to pursue as a project. But perhaps she will not. In any case, none of those things should bother her, for they are externals (reputation is an external according to Epictetus in this very Discourse). She is free to try to change her reputation, but she cannot think it is of true value and remain a stoic.
  
• In Discourse 25, Epictetus says that trustworthiness, decency, and a sense of shame are our own: they are within our power and so are valuable in the stoic sense. Perhaps our "stoic" murderer lacks these things. She surely seems to. What makes them good, however? First, we need to see that they are not externals. Epictetus cannot be speaking of a reputation for trustworthiness here, for that would be an external. Thus he thinks there is a quality trustworthiness that one can lose by thievery (and presumably murder too). One can actually be trustworthy, whether or not one has a reputation for trustworthiness or lack thereof. Likewise a sense of shame and decency can be traits that exist independent of externals such as reputation.
  
• Epictetus has not spoken enough about matters such as shame, decency, and trustworthiness for us to fully understand them, but they must be part and parcel of what it means to be true to one's nature, since that is how they are introduced in Discourse 25 (how could they be "our own" if they are not part of our nature?) And our moral character surely includes more than merely our rational abilities: we are above all rational animals, but we are also social animals. Epictetus has said that being social is part of human nature, and being social, like being rational, has particular virtues associated with it. Trustworthiness, decency, and a sense of shame are plausibly just such virtues. Thus the "stoic" murderer may be rational as rational can be, and yet not true to her nature, in that murder is antithetical to the social virtues, and the social virtues are simply the social side of our nature fully developed. Thus our serial murdere has departed from her nature and "become like a wild beast," as Epictetus says: she has lost track of her human nature. Thus the stoics will not after all countenance a murderer.
• In Discourse 19, we find a key that unlocks this complex of ideas: the claim that we are so constituted by nature that by pursuing our own good, we cannot help but pursue the common interest. The "stoic" serial killer is certainly not pursuing the common interest by relishing murder (unless she's that TV series murderer?).
  
• One last point: the stoic reply suggested earlier, namely that life and death are not valuable per se seemed inadequate, but it reveals an important fact about stoic morals. That fact is that stoics do not consider particular acts evil. They consider particular people evil. Acts are indifferents belonging to the world of externals and as such are neither good nor bad. The moral character of the person doing the act is what matters. Thus serial murdering is not in and of itself evil, but the serial murderer's character is.