The opinions of the thinking part of mankind have been much divided concerning the signification of the term Reason. Every person, conceives himself privileged to reason upon all the subjects of human intelligence; and whatever he may chuse to offer on any side of a question, he denominates his reasons for or against it. By some, this power is held to be the exclusive possession of man; and such persons naturally conclude that an offence is offered to his intellectual dignity, if the smallest portion be conceded to the most docile animals. This is, however, a question for future examination, and will be discussed when their faculties are more particularly investigated. Those who have affirmed that our own species is exclusively gifted with reason, have not in any manner defined the nature of this faculty, or enumerated the steps of the process by which reasoning is performed: indeed, so ambiguous has been the signification annexed to this term, that it is not uncommon to meet, in the best authors, with the expressions of right reason, false or inconclusive reasonings, absurd reasons, &c. These epithets are, however, perfectly correct, as will be demonstrated in the course of this enquiry.

If this capacity of reasoning be peculiar to man, it would not appear difficult to trace the gradations of the process when he employs it: every act of intellectual exertion, deliberately performed, is attended with consciousness; he must therefore be aware of the successive steps of his march: but as this effort might be perplexing to minds unaccustomed to such deliberate and minute investigation, a readier method presents itself in order to attain the object. There are writers in all the departments of human knowledge, who are deservedly held in the highest estimation, and who have reasoned on the subjects they have treated, with the utmost correctness and ability:—let the best specimens of that, which, in these authors, is allowed to be reasoning, be selected and analysed, which will readily demonstrate the means they have pursued to arrive at their conclusion. The whole of this process being conducted by significant sounds conveyed to the ear, or in the signs of these sounds presented to the eye, the inquirer would be immediately impressed, that intelligent sound, or its character, that is, language, must be the vehicle by which this process is performed. In the next place, he would be sensible that these sounds, or their signs, were the substitutes or intended representatives of the objects in nature, either individually or collectively; for he would find that men, by the instrument of speech, had contrived, by a term, equally to express collections as well as individuals; as a man, or an army, which latter might consist of many thousands of the same beings. When he had arrived at this knowledge, he would be persuaded of the importance of these terms, and feel the necessity of their precise and uniform signification, as the representatives of the particular objects or collections they professed to describe:—because, if different significations were affixed to the same term, those who employed it could not mean the same thing. These prefatory observations appear to be proper, and it is important that the reader should bear them in mind; but it will be evident that the most correct description of objects does not constitute the process of reasoning, however indispensable it may be as its foundation.

Reason, as the term itself shows, implies ratio, estimate, proportion, or admeasurement; and in all the instances of reasoning that can be adduced, this interpretation will apply in the strictest sense. But ratio, estimate, &c. involve numbers, by which they can alone be characterised or defined. Thus, by way of illustration, the estimate for a building implies the number of the different materials, with their cost, which is the number of pounds, shillings, and pence; also the number of requisite workmen to be employed for such time, or number of weeks, days, &c. at a certain stipend: admeasurement also consists of numbers, whether it be employed on solids, fluids, or designate the succession of our perceptions, called time[17]: and ratio or proportion is equally the creature of numbers. In a preceding part of these contributions, the importance of numbers has been considered, and a confident belief expressed that no animal is capable of numeration; and that the comprehension of addition and subtraction, the basis of all calculation is exclusively the province of the human intellect. This subject, however, requires a more extended investigation; and the research would doubtless reward the toil of the inquirer.

It is generally acknowledged, that arithmetic, or the combination and separation of numbers, is the purest and most certain system of reasoning, and liable, when properly conducted, to no difference of opinion; because the meaning of number is definite and universally agreed on, there being no nation that affixes a different value to the units, which are the elements of all ulterior numerative progression; and although, in different languages, they are called by different names, as ?e?a [Greek: Deka], decem, dieci, dix,—taihun, tÿn, zehn, tien, ten, yet they have an identical meaning, and denominate the same thing; and notwithstanding the Roman and Arabic symbols are of different character, they represent the same number, whether we employ X or 10. It is owing to this identity of meaning, that the reasoning in numbers is subject to no diversity of opinion.

The names of those things which have an actual existence, and can be submitted to the inquisition of our senses, or are capable of being analysed, are subject to comparatively little error, when we reason concerning them, because their character is defined by observation and experiment: but we have terms to designate that which cannot immediately be submitted to the analytic operations of our senses, and which has no palpable existence; and from the undefined nature of these, the greatest discord and confusion have prevailed when we reason concerning them; as the terms, humanity, charity, benevolence, living principle, organisation, materialism, political expediency, taste, liberty, legitimacy, and a thousand besides.

In order to proceed regularly with this subject, it appears that our reasonings may be employed concerning things, or the objects in nature, and on terms which are not the immediate representatives of natural phenomena, but as they have been denominated general or abstract; and which are intended to be the verbal representatives of multitudes of objects arbitrarily classed, or of opinions comprised under such term.

That reason is not an inherent, peculiar, and independent faculty of the human mind, receives a strong confirmation from considering, that it cannot be voluntarily exerted on subjects of discussion, but requires, as the indispensable condition of its operation, the basis of knowledge, which is to be understood to mean, the result of observation and experiment: for the mere employment of language, on a subject with which we are unacquainted, is but idle prating and a lavishment of words. To reason, is to adapt our means, that is, our knowledge, for the attainment of the end or object proposed: it is the estimate or admeasurement of these means. If, for example, a military commander intended effectually to bombard a city;—such being the object proposed, he would immediately proceed to estimate, admeasure, or calculate his means to produce the effect, and his success would depend on the knowledge he possessed of the nature and properties of the materials employed: he must calculate the distance, elevation, proportionate quantity of powder, and the time the fuzee should burn previously to the explosion of the shell; with various other necessary circumstances. This is an example of a very pure process of reasoning as applied to things, and accords with the definition that has been attempted. If it were necessary to multiply instances of the reasoning on things, perhaps the construction of a thermometer would be a well-adapted illustration; and it would likewise exhibit that which I am very anxious to impress, namely, the very gradual manner in which knowledge, by the operation of reasoning has been applied to the purposes of utility. That many substances, and particularly metallic bodies, augmented in magnitude by being heated, or, as we now term it, expanded by heat, was known many centuries ago, and was a fact of hourly occurrence to the artificers in metals. A similar increment of bulk was also observed in fluids; and it was likewise known, that their dimensions contracted as they cooled. This fact appeared to obtain so generally, that it became an aphorism, that bodies expanded by heat and contracted by cold. Of the precise gradations of heat they were, however, ignorant. Most of the senses became tests, although they were inaccurate criteria. The sight conveyed some distinctive marks; so that when some metallic bodies were heated to a high degree, they were observed to become red, and as the heat was increased, they were rendered white. By the touch, a variety of discriminations of temperature was obtained, to which appropriate terms were annexed, explanatory of its effects, or according with the feelings; as burning, scorching, scalding, blistering hot;—descending to blood, loo, gently, or agreeably warm. The ear was not exempted from its share of information, by detecting the boiling of water, or by discovering when a heated metal was immersed in that fluid, that it was hissing-hot: even the smell detected some obscure traces, sufficient to discourage or invite an approach. These tests, although they might serve for ordinary purposes, were still wholly inadequate for philosophical accuracy. To ascertain quantity, it was necessary to associate number as the index of precision. Notwithstanding the construction of this instrument now appears so simple and easy of contrivance, it is only within a few years that it occurred to fill a tube, having a bulb, with a fluid; and to note the points at which snow dissolved, and water boiled: when these were fixed, the intermediate space might form a scale according to any subdivisions, so as to endow it with precision by the adjunct of numbers. On many occasions, our sensations deceive us, especially in a morbid state of the body: a person in the cold stage of an ague shivers at the temperature that oppresses his attendant with heat; but the instrument described is subject to no variations, by marking the gradations of warmth with the definite character of number. It will now be seen, that man possesses materials for conducting his reasonings, which animals do not enjoy;—by language, and from his capacity of numerating. Speech, of course, involves its record, whereby he can recall the transactions of former ages, and preserve the fruit of experience for his intellectual nurture, when the tree that produced it has perished. This record is the elaboration of the hand,—that wonderful instrument, the register of thought,—that active and and skilful agent that "turns to shape" the contrivances of the mind.

It is perhaps impossible, in a few words, to describe precisely the nature of the operation termed reasoning. In general terms it may be defined, the means we employ for the attainment of the end proposed; the employment of knowledge for the discovery of truth; or the process of demonstration; whether the object be an arithmetical sum, a geometrical problem, or a discourse on taste. A part of the process of reasoning, according to received opinion, consists in comparison, either of things, or of general terms; and this comparison implies not merely their exterior similitude, but likewise their internal structure and composition: because two mineral substances may resemble each other in external appearance, and may wholly differ in their intrinsic properties. The process of ascertaining wherein they agree, and the circumstances which discriminate them, is an instance of reasoning, or the means we employ for the proposed end, and which means necessarily imply the previous possession of knowledge. It will also be seen that in the instance adduced, and indeed in most others, where we reason on things, that precision can only be attained through the medium of number; for these mineral substances, although similar in external character, may contain very different proportions of the precious metals, and their actual value can only be estimated by comparison; that is, by an analysis, founded in knowledge, to ascertain the per centage of gold or silver, which must be expressed in numbers: and the comparison that is instituted concerning general or abstract terms, must have for its basis the establishment of their legitimate force and meaning.

When we consult authorities on this subject, and particularly Dr. Johnson's dictionary, we find that he has given eleven different significations of the term reason, which he defines to be "the power by which man deduces one proposition from another, or proceeds from premises to consequences." There is, however, much ambiguity in this statement; and it would perhaps be impossible, in reasoning concerning things, (which is to be considered as the most perfect example of this process,) to adduce an instance, in which one proposition is strictly deduced from another.

Every proposition is distinct, and independent: numbers, which are definite, may be added together, and the sum-total exhibited, or a lesser number subtracted from a greater, and the remainder shown. It is difficult to say what is really meant by the words "deduces one proposition from another." On examination, it will be found that every simple proposition contains some fact or dictum, something set up or laid down, aliquid propositum; and that nothing can be deduced from it, more than the meaning which the words constituting such proposition legitimately convey: indeed, it must be evident, that any deduction from a simple proposition would destroy its force. The sum of our knowledge consists of individual facts, which are in themselves distinct, as much as a flock of sheep is the aggregate of the different animals that compose it; and it is only a misapplication of language, to affirm that we are able to deduce one proposition from another. One proposition may tend to explain or illustrate another; but every proposition, correctly so termed, relates only to itself.

The other mode by which we reason, is on abstract or general terms, which are not the representatives of individual substances, or the objects of our perceptions; but the names of classes or collections, or of various hypotheses included or designated by a single name. The difficulties which environ this latter mode of reasoning become immediately evident, and satisfactorily account for the hostility and confusion it has engendered, and for the tardy advancement of real knowledge by this medium. The individual objects in nature can be investigated by observation and experiment, and may be sufficiently estimated; but multitudes of objects arbitrarily classed, or imaginary qualities comprehended by a single name, do not admit of the same analysis by the senses, and we are only enabled to ascertain their real meaning in the two ways that have been pointed out,—by authority, which, to be strictly such, ought to be invariable,—or by etymology, which will demonstrate their original signification, and the reasons which imposed them. Thus when we reason concerning charity, benevolence, humanity, and liberty, terms certainly of the highest importance, but each of which involves a variety of circumstances, and the real signification of which, is to this moment differently interpreted, we are impeded in the process, and fail in our estimate, because the dimensions are uncertain. That which one man considers a charitable donation, another views as the means which encourage idleness, and vice, and a third person is perhaps induced to question the motive, by attributing the gift to pride and ostentation. These general terms seldom admit the precision of numbers, but are characterised as to their proportions by expressions equally general and indefinite: as, much, more, and most, to denote their augmentation; and, little, less, least, to define their diminution. These general but indefinite degrees of comparison, as they are termed, once defined the temperature of our atmosphere, until a scale was discovered to mark its increment and diminution by the accuracy of numbers. Great as may be the convenience of general terms, both for abbreviation and dispatch, they are notwithstanding liable to considerable suspicion, and are the frequent sources of error and misapprehension. It has been principally for this reason, that in proportion to the advancement of the physical sciences, the study of scholastic metaphysic has been deservedly neglected.