Euphony seems here to be generally consulted, and the ear may be allowed perhaps to furnish the best rule.
Some form their superlative by adding most to the comparative, as, nether, nethermost; lower, lowermost; under, undermost: others by adding most either to the positive or comparative, as, hind, hindmost, or hindermost; up, upmost or uppermost. From in, we have inmost and innermost[37].
Besides this definite and direct kind of comparison, there is another, which may be termed indefinite or indirect, expressed by the intensive words too, very, exceedingly, &c., as, too good, very hard, exceedingly great.
When the word very, or any other of the same import, is put before the positive, it is called by some writers the superlative of eminence, to distinguish it from the other superlative, which has been already mentioned, and is called the superlative of comparison. Thus, very hard is termed the superlative of eminence; most hard, or hardest, the superlative of comparison.
I have said that the comparative denotes simple excess, and the superlative the greatest. It is not, however, to be hence inferred, that the comparative may not be employed in expressing the same pre-eminence or inferiority with the superlative. If I say, “Of all acquirements virtue is the most valuable,” I may also convey the same sentiment by saying, “Virtue is more valuable than every other acquirement.” If it be asked, what then is the difference between the comparative and superlative? I answer,
1st. That the superlative expresses the absolutely highest or lowest degree of the quality, as when we say, “O God most high;” or the greatest or least degree, in relation merely to the subjects of comparison, thus expressing a superiority of excess above the comparative, as when I say, “In estimating the worth of these human attainments, learning, prudence, and virtue, it cannot be denied that learning is valuable, that prudence is more valuable, but that virtue is the most valuable.” The comparative expresses merely simple excess, but never the highest or lowest degree of the quality. This distinction is, perhaps, the most precise, and the most worthy of attention.
I observe, however, that the sentiment in the last example may be expressed by the comparative, but not simply, or by itself; thus, “Learning is valuable, prudence more valuable, and virtue more valuable still,” the word still implying a continued gradation. Were this word suppressed, the sentence would imply that prudence and virtue are each more valuable than learning, but would assert no superiority of virtue to prudence. The same sentiment may likewise be expressed by combining the two first, and marking simply the excess of the third, thus, “virtue is better than both.”
2dly. When we express the superiority or inferiority of one of two things, or of two aggregates, we almost always use the comparative. Thus, speaking of Cæsar and Cato, I say, “Cato was the more virtuous, Cæsar the more eloquent;” or of two brothers, we say, “John was the elder.”
In such cases the superlative is sometimes employed, as, “the best of the two,” instead of “the better of the two.” The former phraseology, however, is more consonant to established usage, and is in every case to be preferred. “Whether is it easier to say, ‘take up thy bed and walk,’ or to say, ‘thy sins are forgiven thee?’” that is, which of the two is “easier,” not “easiest,” the simple excess of one thing above another being here denoted.
3dly. When we use the superlative, we always compare one thing, or an aggregate number of things, with the class to which they belong, or to which we refer them; whereas, when we use the comparative, except in the case just mentioned, the things compared either belong, or are conceived as belonging, to different classes, being placed in opposition to each other. Thus, in comparing Socrates, who was an Athenian, with the other Athenians, we say, “Socrates was the wisest of the Athenians;” that is, “of,” “out of,” or “of the class of Athenians.” Hence in Latin the superlative often takes the preposition ex (out of) to denote that the object compared belongs to the order of things with which it is compared; the comparative very rarely.