Maarten Maartensz:    Philosophical Dictionary | Filosofisch Woordenboek                      

 S - Should


Should : What both is not (certainly) so and is (probably) so if certain - normal or moral conditions - are the case.

Note that 'should' is normative in two possible senses, namely with reference to factual or desirable conditions, and that in natural language the condition(s) are usually tacit and presupposed. ('You should know what you should do, in the circumstances.')

The logical import of 'should' is not easy to analyse, and if done this is normally done in the context of modal logic.

There also is a subtle interplay with other similar verbs: would, could, might, may, will, can, shall. The common difficulty with these is that they involve some - tacit or explicit - reference to what is not the case, is merely possibly so, is not known to be the case, or is in the or a future, and also involve some - tacit or explicit - reference to conditions of many possible kinds.

Additional complicating factors here are times, tenses, and probabilities.

1. Non-modal analysis of "should":  A - quite possibly too simple but useful - non-modal analysis of "should", speaking about human beings, is as follows:

What a person a should do (and should not do) generally depends, directly or indirectly, on a number of norms of behavior and ends of a certain
social group, where what one should do is what conforms to the norms of behavior or supports the ends of the group, and generally the non-doing of what one should do, if known to others of the group, risks some social punishment or sanction.

And such a person a does do what a should do, by reference to these ends and norms if and only if a when given a choice of options what to do selects that option that best conforms to these ends and norms.


See also: Counterfactual, Modal Logic, Temporal Logic


Gabbay Ed., Lewis, Pollock

 Original: Oct 24, 2007                                                Last edited: 12 December 2011.   Top