Conditions, or conditional sentences, are complex sentences
consisting of a subordinate (or "conditional") clause,
generally introduced by "if" or "unless,"
and a main clause (which may, but need not, have the word "then"
in it). Conditional sentences state something that is/was/may
be the case on the condition of something else that is/was/may
be the case. If that definition leaves something to be desired,
then consider some examples of conditions in English:
To understand the use and translation of conditional sentences
in Latin, it is essential to categorize conditions by type, memorize
which tense and mood of verb characterize those types, and master
the ways to translate the types of condition.
Conditions are sorted by type according to the "reality" or "actualness" of the action/state described in the protasis. There are three main types.
SIMPLE CONDITIONS. The protasis describes something
as fact, past or present:
If he said that, then he was a complete idiot.
If you study Latin, you are a person of impeccable taste and refined habits.
FUTURE CONDITIONS. The protasis states a future
possibility, which may be conceived as either more or less likely
to be true (so that these conditions are further distinguished
as FUTURE MORE VIVID and FUTURE LESS VIVID:
Future more vivid:
If he says that again, I shall flay him alive.
Future less vivid:
If you were to hit me, I would be obliged to hit you back.
CONTRARY TO FACT CONDITIONS (also known as "unreal"
conditions). The protasis states something which is know
to be, or to have been, false. These conditions are
conventionally distinguished according to when the non-fact occurred.
Contrary to fact in present time:
If you were an not a Latin student, you wouldn't be reading this. (But you are a Latin student, so you are reading this.)
Contrary to fact in past time:
If you had been there, you would have laughed. (But you were not there, so you did not laugh.)
The different types (and sub-types) of conditional sentences
can be identified by the kind of verb you find in the two clauses
that constitute the condition. (It will be useful to use
the technical grammatical terms for these clauses: the "if"
clause is called the protasis, and the main clause is known
as the apodosis.) The vital information may be tabulated
as follows:
| Type of Condition | Verb in protasis | Verb in apodosis |
| SIMPLE CONDITIONS | si + indicative (present or any past tense) | indicative (usually same tense as protasis) |
| FUTURE MORE VIVID | si + future perfect indicative | future indicative (or equivalent, e.g. imperative) |
| FUTURE LESS VIVID | si + present subjunctive | present subjunctive |
| CONTRARY TO FACT/PRESENT TIME | si + imperfect subjunctive | imperfect subjunctive |
| CONTRARY TO FACT/PAST TIME | si + pluperfect subjunctive | pluperfect subjunctive |
It is possible for conditions to be "mixed," i.e.
start out as future less vivid in the protasis, and then become
a simple, factual condition in the apodosis; but don't worry about
such mutations for the time being.
The simplest way to explain translation is to provide examples which may serve as paradigms. The salient verbs in the Latin conditions, and their appropriate translation into English, are italicized.
si Quintus carmina componit, Maecenas ea legit.
If Quintus writes poems, Maecenas reads them.
si Quintus carmina composuit, Maecenas ea legit.
If Quintus wrote poems, Maecenas read them.
si Quintus carmina composuerit, Maecenas ea leget.
If Quintus writes* poems, Maecenas will read them.
FUTURE LESS VIVID CONDITIONS:
si Quintus carmina componat, Maecenas ea legat.
If Quintus were to write** poems, Maecenas would read them.
-or-
If Quintus should write poems, Maecenas would read them.
si Quintus carmina componeret, Maecenas ea legeret.
If Quintus were writing** poems, Maecenas would read them.
CONTRARY TO FACT/PAST TIME:
si Quintus carmina composuisset, Maecenas ea legisset.
If Quintus had written poems, Maecenas would have readthem.