Authors/Ockham/Summa Logicae/Book III-2/Chapter 28

Latin	English
CAP. 28. QUOMODO TERMINATUR QUAESTIO QUID EST; ET PRIMO DE DEFINITIONE.	Chapter 28. How the question what is is settled, and first on definition
Viso quomodo terminatur quaestio si est, videndum est quomodo terminatur quaestio quid est. Et hoc est in sciendo quomodo potest evidenter cognosci propositio in qua praedicatur definitio de definito.	Having seen how the question of "if is" is settled, we must see how the question of "what is" is settled. And this is in knowing how the proposition in which the definition is predicated of the defined can be clearly known.
Est autem primo sciendum quod definitionum quaedam est definitio exprimens quid nominis et quaedam est definitio exprimens quid rei. Definitio exprimens quid rei est illa definitio quae non est necessaria disputanti scienti significatum vocabuli; sicut ad hoc quod aliquis sciat quid significat hoc nomen ‘homo’, non est necessarium scire quod homo componitur ex tot partibus vel ex talibus partibus. Unde quilibet potest disputare cum alio, quamvis ignoret definitionem exprimentem quid rei, sed ignorata definitione exprimente quid nominis non potest ƿ quis cum alio disputare.	But first of all it must be known that there is a certain definition expressing the meaning of a name and a certain definition expressing the meaning of a thing. A definition expressing what a thing is is that definition which is not necessary to the disputant who knows the meaning of the term; just as in order for someone to know what this name 'man' means, it is not necessary to know that man is composed of so many parts or of such parts. Wherefore any one may argue with another, although he is ignorant of the definition expressing what is the matter, but without knowing the definition expressing what a name is, no one can argue with another.
Et ideo quando quis addiscit significata vocabulorum, tunc addiscit definitiones exprimentes quid nominis, quamvis non addiscat definitiones exprimentes quid rei. Non est igitur definitio exprimens quid rei necessaria disputanti, quia talis non tantum exprimit quid nomen significat, sed etiam exprimit quid res est.	And therefore when someone learns the meanings of terms, then he learns the definitions expressing the meaning of the name, although he does not learn the definitions expressing the meaning of the thing. It is therefore not a definition expressing what is necessary for the disputant, because such a definition does not only express what the name signifies, but also what the thing is.
Talis autem definitio duplex est.	But such a definition is twofold.
Quaedam enim definitio talis est quae nihil importat extrinsecum rei alio modo quam importat rem vel partem rei. Et talis definitio vocatur definitio propriissime dicta, quae non potest esse nisi substantiarum vel nominum substantiarum, quia talis definitio non potest esse nisi compositorum, tamquam illorum quorum essentia exprimitur per orationem, cuiusmodi composita per se una non sunt nisi substantiae.	For there is a certain definition which conveys nothing external to a thing in any other way than it conveys a thing or a part of a thing. And such a definition is most properly called a definition, which can only be of substances or the names of substances, because such a definition can only be of composites, as those whose essence is expressed by speech, such composites are in themselves only substances.
Talis definitio est ista ‘animal rationale’; sit ‘animal’ genus et ‘rationale’ differentia, quia ‘animal’ importat totum hominem et ‘rationale’ importat partem hominis sicut suum abstractum.	Such a definition is that example 'rational animal'; let 'animal' be the genus and 'rational' the difference, because 'animal' implies the whole man and 'rational' implies a part of man as its abstract.
Alia est definitio importans quid rei, quae simul cum hoc quod importat rem, importat vel exprimit aliquid quod non est de essentia rei; sicut definitio animae, quae est ista ‘actus corporis physici organici’ etc. importat animam et corpus, quod non est pars animae nec anima.	There is another definition of the meaning of a thing, which, at the same time as that which signifies a thing, conveys or expresses something which is not of the essence of the thing; as the definition of the soul, which is that statement 'act of the organic physical body' etc. It signifies the soul and the body, which is neither part of the soul nor the soul.
Et ista vocatur definitio per additamentum. Et tales definitiones importantes quid rei convertuntur cum nominibus mere absolutis affirmativis.	And this is called definition by addition. And such important definitions of what things are, are converted into purely positive absolute names.
Aliae sunt definitiones importantes quid nominis, quae non sunt nisi orationes exprimentes quid significant nomina. Et tales definitiones propriissime sunt nominum negativorum et connotativorum et respectivorum, sicut ista definitio ‘habens albedinem’ sive ‘informatum albedine’ non exprimit nisi quid significat hoc nomen ‘album’.	There are other important definitions of what a name means, which are nothing but speeches expressing what the names mean. And such definitions are very proper of negative and connotative and respective nouns, just as this definition 'having whiteness' or 'informed by whiteness' does not express anything other than what this word 'white' means.
Unde ista definitio est necessaria cuilibet cum alio disputanti.	Hence this definition is necessary for anyone disputing with another.