Traditional grammars divide the conditions into three categories:
- Logical and General Conditions that refer to facts in the present or past and can be general or particular.
- Contrafactual conditions, or conditions that refer to the present or past and clearly imply that the outcome (the consequence, the "then-clause") did not happen because the condition was not fulfilled (e.g., "If you were here [but you aren't], I would be happy [but I'm sad].").
- Future Conditions that imagine events yet to come either "more vividly" with the future indicative (as in, "If you will visit you mother, she will be happy.") or "less vividly" with the present subjunctive (as in, "If you should complete your work on time, you would earn a better mark.").
Today, most grammarians believe that the distinction between "more vivid" and "less vivid" is an inaccurate one and that it is misleading to think that vividness has anything to do with the use of the subjunctive. In fact, it simply makes more sense to notice, first, that the distinction between 1 (Indicative conditions) and 2 (Contrafactual conditions) above is formally a distinction between the indicative and the subjunctive mood; and, second, that the distinction between the "more vivid" and the "less vivid" condition is similarly a distinction between the indicative and the subjunctive mood. Having made this observation, we may ask if we can simplify the description by attending to what the moods have in common: the subjunctive is used to imagine or present a potential event or the potential result of an event; the indicative is used to imagine or present an actual event or the actual result of an event.
This means that a neater and more precisely grammatical distinction can be made between the indicative conditions and the subjunctive conditions. See the overview of conditions.