Mode
Most languages are so constructed, that the verbs change their terminations for the purpose of expressing the manner of being or action. In this particular, the English is singular; there being but one inflection of a single verb, which can be said to be peculiar to the conditional or subjunctive mode.108 In all other respects, the verbs in the declaratory and conditional modes are the same; and the condition is known only by some other word prefixed to the verb.
It is astonishing to see how long and how stupidly English grammarians have followed the Latin grammars in their divisions of time and mode; but in particular the latter. By this means, we often find may, can, should and must in a conditional mode, when they are positive declarations and belong to the indicative. All unconditional declarations, whether of an action, or of a right, power or necessity of doing an action, belong to the indicative; and the distinction between the indicative and potential is totally useless. Should is commonly placed in the imperfect time of the subjunctive; yet is frequently used to express an unconditional obligation, as he should go; and belongs to the present time of the indicative, as much as he ought, or the French il faut or il doit.
Would is sometimes employed in a declaratory sense to express a present volition, and then belongs to the indicative. In the past time, should, would, might, could, often express unconditional ideas, and belong to the indicative. In short, the usual arrangement of the English verbs and auxiliaries in our grammars is calculated to perplex and mislead a learner; and I have never found a foreigner who could use them with tolerable propriety.