Neither will simple connection,—I am wrong because you are right.
But, the two combined constitute the construction in question,—if I be wrong, you are right.
Now, a conjunction that connects two certain propositions may be said to govern an indicative mood.
And a conjunction that connects an uncertain proposition with a certain one, may be said to govern a subjunctive mood.
The government of mood is the only form of government of which conjunctions are capable.
[§ 609]. Previous to the question of the government of conjunctions in the way of mood, it is necessary to notice certain points of agreement between them and the relative pronouns; inasmuch as, in many cases, the relative pronoun exerts the same government, in the way of determining the mood of the verb, as the conjunction.
Between the relative pronouns and conjunctions in general there is this point of connection,—both join propositions. Wherever there is a relative, there is a second proposition. So there is wherever there is a conjunction.
Between certain relative pronouns and those particular conjunctions that govern a subjunctive mood there is also a point of connection. Both suggest an element of uncertainty or indefinitude. This the relative pronouns do, through the logical elements common to them and to the interrogatives: these latter essentially suggesting the idea of doubt. Wherever the person, or thing, connected with an action, and expressed by a relative be indefinite, there is room for the use
a subjunctive mood. Thus—he that troubled you shall bear his judgment, whosoever he be.
[§ 610]. By considering the nature of such words as when, their origin as relatives on the one hand, and their conjunctional character on the other hand, we are prepared for finding a relative element in words like till, until, before, as long as, &c. These can all be expanded into expressions like until the time when, during the time when, &c. Hence, in an expression like seek out his wickedness till thou find (not findest) none, the principle of the construction is nearly the same as in he that troubled you, &c., or vice versâ.[[63]]