An idea of the scholastic discussion of the classification of sciences may be had by following Albertus Magnus’s ponderous approach to a consideration of logic: whether it be a science, and, if so, what place should be allotted it. We draw from the opening of his liber on the Predicables,[439] that is to say, his exposition of Porphyry’s Introduction. Albert will consider “what kind of a science (qualis scientia) logic may be, and whether it is any part of philosophy; what need there is of it, and what may be its use; then of what it treats, and what are its divisions.” The ancients seem to have disagreed, some saying that logic is no science, since it is rather a modus (mode, manner or method) of every science or branch of knowledge. But these, continues Albertus, have not reflected that although there are many sciences, and each has its special modus, yet there is one modus common to all sciences, pertaining to that which is common to them all: the principle, to wit, that through reason’s inquiry, from what is known one arrives at knowledge of the unknown. This mode or method common to every science may be considered in itself, and so may be the subject of a special science. After further balancing of the reasons and authorities pro and con, Albertus concludes:
“It is therefore clear that logic is a special science just as in ironworking there is the special art of making a hammer, yet its use pertains to everything made by the ironworker’s craft. So this process of discovering the unknown through the known, is something special, and may be studied as a special art and science; yet the use of it pertains to all sciences.”
He next considers whether logic is a part of philosophy. Some say no, since there are (as they say) only three divisions of philosophy, physics, mathematics, and metaphysics; others say that logic is a modus of philosophy and not one of its divisions. But, on the contrary, it is shown by others that this view of philosophy omits the practical side, for philosophy’s scope comprehends the truth of everything which man may understand, including the truth of that which is in ourselves, and strives to comprehend both truth and the process of advancing from the known to a knowledge of the unknown. These point out that
“... the Peripatetics divided philosophy first into three parts, to wit, into physicam generaliter dictam, and ethicam generaliter dictam and rationalem likewise taken broadly. I call physica generaliter dicta that which embraces scientia naturalis, disciplinalis, and divina (i.e. physics in a narrower sense, mathematics which is called scientia disciplinalis, and metaphysics which is scientia divina). And I call ethica, that which, broadly taken, contains the scientia monastica, oeconomica and civilis. And I call that the scientia rationalis, broadly taken, which includes every mode of proceeding from the known to the unknown. From which it is evident that logic is a part of philosophy.”
And finally it may be shown that
“if anything is within the scope of philosophy it must be that without which philosophy cannot reach any knowledge. He who is ignorant of logic can acquire no perfect cognition of the unknown, because he is ignorant of the way in which he should proceed from the known to the unknown.”
From these latter arguments, approved by him and in part stated as his own, Albertus advances to a classification of the parts of logic, which he makes to include rhetoric, poetics, and dialectic, and to be demonstrative, sophistical or disputatious, according to the use to which logic (broadly taken) is applied and the manner in which it may in each case proceed, in advancing from the known to some farther ascertainment or demonstration.[440] Soon after this, in discussing the subject of this science, Albertus points out how logic differs from rhetoric and poetics, although with them it may treat of sermo, or speech, and be called a scientia sermonalis; for, unlike them, it treats of sermo merely as a means of drawing conclusions, and not in and for itself.
From the purely philosophical division of the sciences we pass to the hybrid arrangement adopted by Vincent of Beauvais, who died in 1264. This man was a prodigious devourer of books, and for a sufficient pabulum, St. Louis set before him his collection of twelve hundred volumes. Thereupon Vincent compiled the most famous of mediaeval encyclopaedias, employing in that labour enormous diligence and a number of assistants. His ponderous Speculum majus is drawn from the most serviceable sources, including the works of Albertus, his contemporary, and great scholastics like Hugo of St. Victor, who were no more. It consisted of the Speculum naturale, doctrinale, and historiale; and a fourth, the Speculum morale, was added by a later hand.[441] Turning its leaves, and reading snatches here and there, especially from its Prologues, we shall gain a sufficient illustration of the arrangement of topics followed by this writer, whose faculties seem to drown in his shoreless undertaking.[442]
In his turgid generalis prologus to the Speculum naturale, Vincent presents his motives for collecting in one volume
“... certain flowers according to my modicum of faculty, gathered from every one I have been able to read, whether of our Catholic Doctors or the Gentile philosophers and poets. Especially have I drawn from them what seemed to pertain either to the building up of our dogma, or to moral instruction, or to the incitement of charity’s devotion, or to the mystic exposition of divine Scripture, or to the manifest or symbolical explanation of its truth. Thus by one grand opus I would appease my studiousness, and perchance, by my labours, profit those who, like me, try to read as many books as possible, and cull their flowers. Indeed of making many books there is no end, and neither is the eye of the curious reader satisfied, nor the ear of the auditor.”