The JSLint license specifies that code "shall be used for Good, not Evil". It's been a source of (what appears to be) alarmist and ridiculously overblown controversy for a while now.

I've noticed this conversation tends to attract a lot of developers who really like open source, know next to nothing about the law, and reach the conclusion that this might have real legal implications.

I'll freely admit I'm a developer who knows next to nothing about the law, but it seems obvious that since the license makes no attempt to precisely define either "good" or "evil", and they don't already have legal definitions (as far as I know), or even consistent definitions in common parlance, no sane judge would attempt to enforce that part of the license.

Then again, my uninformed opinion is just as uninformed as all the uninformed opinions I'm disagreeing with, so I could be completely off base with my analysis.

So what is the worst thing that could (realistically, legally) happen to someone using JSLint because of that specific section of the license?

  • The law concerns itself with lawful and unlawful; good and evil is the province of theology and morality.
    – Dale M
    Aug 8, 2015 at 0:51
  • Lawful is also in the province of morality, in some systems :). Aug 8, 2015 at 11:15

2 Answers 2


It would be very difficult for a court to make a judgment based on this specific provision of the JSLint license, for the simple fact that good and evil, except perhaps at the very extremes of the scale, are inherently subjective and contextual terms.

The wording of this provision is such that it is likely that if a court were required to consider it, it would need to fall back, so to speak, to a consideration of whether a reasonable person would find the code acceptable or not, or otherwise, whether a reasonable person would find the purpose of the software acceptable or not.


Short Answer

The entire license could be ruled invalid and therefore unenforceable.


Two legal principles at play in jimsug's answer might be:

Either or both of which might be sufficient for a judge to waive enforcement of any provisions that relate to the terms "good" or "evil."

An interesting side effect of this might be that unless the principle of severability were applied to the JSlint license, then the license could be considered completely invalid due solely to the addition of the words "good" and "evil." A judge would have to affirmatively impose severability because the license itself does not assert it.

  • I think these two doctrines only apply to laws, not contracts. But I think you are right, this clause is unenforceable.
    – Viktor
    Sep 13, 2015 at 12:49
  • "Vague and overly broad" is a common objection to discovery requests. Legal principles, once established, are often applied universally. Contract common law and statutory law formally merge with the legal principle of contra bonos mores — which means contracts that concern illegal, immoral acts or acts otherwise contrary to public policy are not enforceable. @Viktor Sep 13, 2015 at 17:17

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