Consequentialism is the ethical theory that holds that whether an act is morally good depends only on the consequences.

Stanford Encyclopedia of Philosophy


Consequentialism is better seen as a family of ethical theories than as an ethical paradigm. The focus is on why certain acts are morally good (bad or neutral). Specifically, it’s not due to the intrinsic nature of the act or the circumstances surrounding the act, which distinguishes the theories from some deontological and virtue ethics theories. 

Strictly speaking, consequentialism does not need to be utilitarian, e.g., the justification for a rule such as, “do not lie”, could be made by reference to claims about the consequences. Generally, consequentialism is used to refer to descendants of utilitarianism1See SEP. which may generalize beyond utility in the sense of measuring satisfaction alone while still adhering to the utilitarian paradigm2State consequentialism, for example, optimizes for the welfare of the state, which is not a direct aggregate of individual welfare..

I found formalizing the consequentialist claim challenging: notions of dependence have not been formalized in SUMO and the precise meaning is unclear. Consequentialism’s claim is agnostic as to which protocol is used to determine whether an act is morally good or not. Formal precision seems to ask for less vagueness than is inherent in the definition. 

Perhaps one could say that a justified ethical theory is consequentialist if all physical premises in the justifying arguments are consequences of the action under consideration, i.e., the moral judgments only depend on physical consequences and abstract entities, such as ethical axioms and inference rules.

Another approach is to focus on consequentialist utilitarianism and to provide a constraint on the applicable utility functions so that anything influencing the output of the utility function is a possible outcome of the action concerned.


(documentation Consequentialism EnglishLanguage "Consequentialism is a moral theory that holds 
that 'whether an act is morally right depends only on consequences (as opposed to the circumstances 
or the intrinsic nature of the act or anything that happens before the act)' (Stanford Encyclopedia of Philosophy).")
(subclass Consequentialism Utilitarianism)    

(documentation ConsequentialistTheory EnglishLanguage "A set of consequentialist sentences.")
(subclass ConsequentialistTheory UtilitarianTheory)

(theoryPhilosophyPair Consequentialism ConsequentialistTheory)

  (instance ?CUT ConsequentialistTheory)
  (forall (?S)
      (element ?S ?CUT)
      (forall (?P ?UF ?FORMULA)
            (part ?P ?S)
            (equal ?P (AssignmentFn ?UF ?FORMULA))
            (instance ?FORMULA Formula)
            (instance ?UF UtilityFormulaFn))
          (instance ?UF ConsequentialistUtilityFormulaFn))))))

Consequentialism is defined as a subclass of utilitarianism where, for all theories, each instance of a utility function is a consequentialist utility function.

(documentation ConsequentialistUtilityFormulaFn EnglishLanguage "A UnaryFunction that maps Formulas to the net utility 
of that which is described where the utility measurement only depends on the consequences of an action.")
(subclass ConsequentialistUtilityFormulaFn UtilityFormulaFn)

  (instance ?UF ConsequentialistUtilityFormulaFn)
  (domain ?UF 1 ActionFormula))

    (instance ?UF ConsequentialistUtilityFormulaFn)
    (realizesFormulaSubclass ?CPROC ?FORMULA)
    (subclass ?CPROC AutonomousAgentProcess))
  (forall (?X)
      (influences ?X (ConsequentialistUtilityFormulaFn ?FORMULA))
        (instance ?X Outcome)
          (exists (?IPROC)
              (instance ?IPROC ?CPROC)
              (result ?IPROC ?X))) Possibility)))))

Consequentialist utility functions are defined as a subclass of utility functions. The domain is limited to action formulas that can be realized by a class of actions. For every consequentialist utility function, formula, and class of actions, every entity that influences the output of the function is a physical outcome and a possible result of some instance of this class of actions3I welcome suggestions as to more concrete ways to approach this..

(documentation influences EnglishLanguage "The influence relation between instances of Entities (influences ?ENTITY1 ?ENTITY2 denotes that ?ENTITY has some effect on ?ENTITY2")
(domain influences 1 Entity)
(domain influences 2 Entity)
(instance influences BinaryPredicate)
(relatedInternalConcept influences causes)

  (causes ?P1 ?P2)
  (influences ?P1 ?P2))

  (influences ?E1 ?E2)
  (exists (?CHANGE ?PROCESS)
      (instance ?CHANGE Change)
      (patient ?CHANGE ?E2)
      (causes ?PROCESS ?CHANGE)
      (involvedInEvent ?PROCESS ?E1))))

I chose a weak ontology-level definition for influences. First, if process P1 causes P2, then P1 influences P2. Next, if entity E1 influences E2, then there exists a change C to E2 and a process P that causes C such that E1 is involved in P. The reverse implication should hold in the case that E1 is the agent in P. Some other case roles, yet not all, may also qualify as having an influence.