Universa Philosophia

The mode of knowing is used in various ways. First, for any act of knowing whatsoever: which is a mode tending scientifically to the thing known. Secondly, for the logical faculty, which is called modus sciendi: because it itself teaches the mode of knowing to be observed in the other sciences: on that account Aristotle said that it is absurd to seek science and the mode of knowing at the same time: that is, that the real sciences, Philosophy, Medicine, etc., are not to be investigated at the same time as Logic, because this precedes the others. Thirdly, it is used for certain acts of the intellect and their objects: which are called diffinitio, divisio, et argumentatio: because these acts explain their objects, which had been known by other acts inexplicitly. For example, someone knows man by the concept which is called homo: by which both the expert and the inexpert conceive, which cognition is very confused, and through accidents not sufficiently explaining the nature of man: but if you define man as animal rationale, you now explain him. Definition therefore is on that account a mode of knowing.

Which comprises diffinitionem, divisionem, et argumentationem: nor is there another mode of knowing in this third acceptance. Likewise modus sciendi is divided into formal and objective. The formal are the acts of the intellect themselves, by which we define, divide, and argue. The objective are the things themselves or the objects, which are defined, divided, and argued. For example, I say, est homo rationale: there are in my intellect acts by which I say it, these are called definitio formalis; there are besides on the part of the known object animal rationale, which are called definitio obiectiva. Observe these, because many things are said of the mode of knowing which do not belong to the acts alone: many likewise which do not belong to the objects alone, but all fit the mode of knowing: because some fit the formal, and some the objective.

Definition, from Aristotle, first of Topics, ch. 4, is oratio significans, quod quid est rei: that is, explicans naturam rei. Oratio is not taken for the vocal utterance alone, for thus the definition would be mutilated: but oratio is taken generally for the act of the intellect signifying the quiddity or nature of a thing by voice or writing. For example, man is composed physically of body and soul: he can be defined, homo constat ex corpore, et anima. He is composed likewise logically of animal and rational, and can thus be defined, homo est animal rationale: where corpus, et anima, animal, et rationale, are the nature showing the quiddity of man, they are not the oratio explaining the nature of the thing, they are the nature of the thing itself explained through the oratio, which nature of the thing explains the defined: that is, they bring it about that the defined is perfectly known, therefore it is objective definition: because in the account of object it has to explain what homo (which is the defined) has confusedly and as it were involvedly.

It is called definitio, not because it puts an end to the object, but because it itself is bound to one object, so as not to wander through others as a confused act wanders: for animal and rationale are so proper to man that a clear cognition of them belongs to man alone, at whom that cognition is terminated. But if you said, homo est animal bipes, man would not be defined: because to have two feet belongs as much to the crane as to man. Wherefore if God cannot be defined, it is not because he lacks an end, but because he cannot be known quidditatively in this life; as neither can the other separate substances. But he can be defined imperfectly: because he has an account somehow common with creatures, and a difference proper to himself.

Aristotle, 3 Metaph., ch. 3, says that all things are known through definition: but that genus is the principle of definition: whence the dialectical adage flowed, Definitio constat genere, et differentia: because it ought to represent the genus and the difference. The proximate genus indeed, in which several species agree, but an essential difference, as animal rationale is the definition of man: because animal is the genus in which homo and leo proximately agree: but rational is the difference by which man essentially differs from them: but if the difference be accidental, it will not properly be a definition, but a description. Logical definition consists of genus and difference; but physical definition consists only of two specific parts: as man of body and rational soul. But body is somehow common also to the lion, yet it is not a genus. All genera can be defined, but individuals not so well: review disp. 10 of logic, sect. 2.

Laws of definition. The first, that definitio, et definitum convertantur: that is, that the consequence from one to the other be valid. The second, that it ought to belong to every defined thing, and not to others: which second rule is contained in the first; an example of both: est homo, therefore est animal rationale: est animal rationale, therefore est homo: and so animal rationale belongs to all men, and not to others. The third rule, a definition is clearer than its defined, proper, not metaphorical: for if anyone, to define sleep, should say, somnus est mortis imago, he has said nothing; which phrases are suited to poets and orators: but to the Dialectician none is suited except a clear and brief one: wherefore Aristotle compared the orator to the palm of the hand; but the Dialectician to the fist: because the latter speaks compressedly, the former diffusely. If anyone asks, which is this definition? Answer Physical, or Logical. But if you are asked of what sort is this definition? Answer good or bad, and do not say true or false: because it can be true and bad, because it is not converted with the defined, as homo est animal bipes is bad and true; but if the definition is good, it is necessarily true.

The second mode of knowing is division. Physical division is the disjoining and separation of two parts: as when wood is cut into two parts. By a trope, logical division is indeed a dividing act of the intellect, and as it were cuts the object into its parts. Logical division is therefore: Oratio explicans naturam rei per partes: it agrees with definition in those words, oratio explicans naturam rei: but it differs in this, per partes: and so every object consisting of parts, when it is clearly known through them, is divided by the intellect. But some parts are logical, as genus and difference: others physical: thus one division is logical, another physical: namely physical which knows physical parts, but logical which knows logical parts. For example, man is composed logically of genus and difference, likewise he is composed physically of body and rational soul: the act of the intellect knowing the parts of man to be animal and rational is the logical division of man; but if it knows his parts to be body and soul, it is physical division, not because it divides the object physically, but because it represents its physical parts. In which case homo, e.g., is the divisum: but animal and rationale, or corpus, et anima, are the partes dividentes. Likewise a common account is divided into its inferiors: as homo in Petrum, et Paulum; and animal, in hominem, et equum.

That division is a mode of knowing is clear: because man is more explained through the concept of animal rational than through the concept of man, as I said. §. 1. and 3. Likewise animal is more perfectly known in man and horse than without them. That every division is distinguished from definition is commonly asserted: but I do not grasp that: because the definition of man attains in itself the parts of man as clearly and explicitly as division does: for it knows altogether the same parts as definition, and in the same way. I grant that the division of a common account into its inferiors is distinguished from the definition of the same common account. For example, man is divided into Peter and Paul, yet is not defined through Peter and Paul, but through animal rationale, on which matter I treated more abundantly, disp. 10 of Logic, sect. 6.

Laws of division. The first, that the divided contain in itself all the dividing extremes, otherwise the division is bad and false, as if you say animal aliud homo, aliud Angelus: every dividing part therefore ought to be a participant of the divided. The second rule, the divided is not convertible with the individual dividers: because the divisum contains other parts beyond one divider, as man contains under himself Peter and others: but all the dividers together are equal to the divided, for man, lion, and the other animals are equal to animal, and this to them. The third law, that the individual dividers be distinguished among themselves: for example, animal, aliud homo, aliud leo: but if you said, animal aliud homo, aliud rationale, it would be faulty: because homo and rationale are not distinct animals, but the same.