Moral Nihilism

Moral Nihilism is the view that nothing is morally wrong.

Stanford Encyclopedia of Philosophy

Moral Nihilism is the view that there are no moral facts.

Ethics: The Fundamentals

Discussion

Moral Nihilism¹I prefer Wikipedia‘s discussion to SEP’s. is a meta-ethical stance that encompasses a wide array of claims that the field of ethics and morality is not substantially meaningful. In other words, we should not recourse to ethical reasoning as a part of figuring out what to do or what to allow in our societies. Thus moral nihilism makes a negative claim.

There are many varieties of moral nihilism, or more broadly, moral skepticism. There are many stances to be adopted in the middle: for example, expressivism is a quasi-realist theory that (morally) “good” and “bad” are attitudinal evaluatory expressions. This provides a clear semantics to evaluate ethical statements, so it’s non-nihilistic, yet these evaluations are not necessarily objective features of the world, so it’s non-realistic²I could argue that a theorem claiming that all rational agents with properties Ps should evaluate situation S in the same way could be both expressivist and realist. I am more skeptical of the final nature of meta-ethical stances than of moral theory itself. See the first worklog for some discussion..

I chose to formalize some simple, strong negative claims about the existence of moral theories. In addition to the two definitions above, I sketch the claim that there is no true, justified moral theory.

SUMO

(documentation MoralNihilism EnglishLanguage 
"'Moral Nihilism is the view that nothing is morally wrong' (SEP - Moral Skepticism). 
Moral Nihilism can also be defined as 'the view that there are no moral facts' (Ethics: The Fundamentals).")
(subclass MoralNihilism Ethics)

(documentation MoralNihilismTheory EnglishLanguage "A set of sentences describing a moral nihilistic stance.")
(subclass MoralNihilismTheory MetaEthicalTheory)

(theoryFieldPairSubclass MoralNihilism MoralNihilismTheory)

(documentation NoMoralWrongTheory EnglishLanguage "A moral nihilistic theory asserting that nothing is morally wrong.")
(subclass NoMoralWrongTheory MoralNihilismTheory)

(documentation NoMoralFactsTheory EnglishLanguage "A moral nihilistic theory asserting that there are no moral facts.")
(subclass NoMoralFactsTheory MoralNihilismTheory)

(documentation NoJustifiedTrueEthicalTheory EnglishLanguage "A moral nihilistic theory asserting that there is no justified true ethical theory.")
(subclass NoJustifiedTrueEthicalTheory MoralNihilismTheory)

Moral nihilism is defined as a meta-ethical theory to avoid potential self-referential issues whereby a moral nihilistic theory may claim that there are no true ethical theories, which would include itself. Three subclasses are defined: theories claiming there are no moral wrongs, no moral facts, and no true justified ethical theory.

(<=>
  (instance NMWT NoMoralWrongTheory)
  (exists (?MNS)
    (and
      (element ?MNS ?NMWT)
      (equal ?MNS
        (not exists (?MW)
          (modalAttribute ?MW MorallyBad))))))

A no moral wrongs theory contains a sentence claiming that there does not exist any formula that is morally wrong. This will contradict any ethical theory that entails any morally wrong judgment, thus preventing the capacity to classically reason about ethical judgments.

(<=>
  (instance ?NMFT NoMoralFactsTheory)
  (exists (?MNS)
    (and
      (element ?MNS ?NMFT)
      (equal ?MNS 
        (not exists (?TMT)
          (and
            (instance ?TMT EthicalTheory)
            (forall (?S)
              (=>
                (element ?S ?TMT)
                (instance ?S Fact)))))))))

A no moral facts theory contains a sentence claiming that there does not exist a true moral theory whose every sentence is a fact³Which, in SUMO’s KB, simply means that the sentence is true..

(<=>
  (instance ?NJTMT NoJustifiedTrueEthicalTheory)
  (exists (?MNS)
    (and
      (element ?MNS ?NJTMT)
      (equal ?MNS
        (not exists (?NJTMT)
          (and
            (instance ?JTMT EthicalTheory)
            (instance ?JTMT JustifiedTrueTheory)))))))

A no justified true ethical theory contains a sentence claiming that there does not exist a justified true ethical theory. A justified true ethical theory is a justified theory for which every arguement is a valid, deductive argument and for which all premises are true.