Definition by genus and differentia

The two preceding types of definition are essentially relational, defining a word’s meaning through its connections with other words. They may often be workable as cognitive definitional strategies, but they are unlikely to be successful as extensional definitions. This is because they leave the essential nature of the definiendum’s meaning to be worked out by the definition’s addressee, and as a result carry the risk that the wrong meaning may be inferred: in the case of bocal, for example, what is it that jars and con serve pots have in common, that makes them a bocal? Smallness? A wide opening? Function? The only way to convey this essential nature, apparently, is the strategy of definition by genus and differentia, henceforth GD definition, the theory of which was developed by Aristotle in the Posterior Analytics (Tredennick 1960: XIII.96a ff.). According to Aristotle, definition involves specifying the broader class to which the definiendum belongs (often called the definiendum’s genus), and then showing the distinguishing feature of the definiendum (the differentia) which distinguishes it from the other members of this broader class. A classic example of GD definition is the definition of man (in the sense of ‘human being’) as ‘rational animal’. This definition names the broader class of entities to which man belongs – animals – and specifies the distinguishing feature which picks man out from the other members of the class of animals – rationality. Needless to say, many aspects of this definition might well be contested. Nevertheless, its status as an example of definition by genus and differentia should be clear.

 For many definienda, GD definition seems to be almost inevitable. Inherent in the idea of saying what something is seems to be the idea of saying what sort of thing it is, and what makes it different from other examples of the same sort. Often, GD definition is a useful strategy of cognitive definition.

Thus, many definitions in dictionaries explicitly or implicitly exemplify this strategy. An example is the Concise Oxford’s (2004) definition of the noun keg as ‘small barrel’: the definition shows the larger class to which the definiendum belongs (barrel), and specifies that it is distinguished from other members of this class by the quality of smallness. Similarly, the definition of the verb pay as ‘give a person what is due for services done’ contains the information that paying is a type of transfer (‘give’), with the specification that it is transfer of something that ‘is due for services done’.

There are many problem cases, however, where GD definition may be either ineffective or, simply, impossible. This is particularly so if the GD definition is intended as a cognitive definition. The reason for this is as follows. GD definition presupposes a system of categories or genera according to which definienda can be classed: defining man as ‘rational animal’ presupposes that the addressee already knows the meanings of those two terms. But there is not a large number of genera and differentiae to work with: for many words, the relevant genus will not be familiar to the definition’s addressee, and hence GD definition won’t be an effective strategy for a cognitive definition. Consider for example a definition of give as ‘transfer the possession of freely’ (Concise Oxford). The category of transfer, arguably, is too abstract and ambiguous to serve as an illuminating genus forgive, and, as a result, its use in a definition of give may not be cognitively successful. For what is it to transfer something? One possible answer is that transferring something is sending it: if I transfer some money to you, I send you some money. Thus, if the definition’s addressee interprets the idea of transfer as ‘sending’, then give will be defined as ‘send the possession of freely’, a formulation which does not necessarily make any sense. On the other hand, transfer might be interpreted as ‘moving’: if I transfer books from one room to another, I am moving them. On this interpretation, give will mean something like ‘move the possession of freely’, a definition which is also unsatisfactory.

These problems are less serious for extensional GD definitions, which are not concerned with ease of understandability. Consider, for example, the following definition of feather:

one of the light horny epidermal outgrowths that form the external covering of the body of birds and that consist of a shaft bearing on each side a series of barbs which bear barbules which in turn bear barbicels commonly ending in hooked hamuli and interlocking with the barbules of an adjacent barb to link the barbs in a continuous vane (Webster’s Ninth New Collegiate Dictionary: feather; quoted in Landau 1984: 134–135)

This situates feather within the larger class of horny epidermal outgrowth, but the terms in which this and the differentiae are couched makes them inaccessible to anyone who lacks specialist ornithological knowledge: given this definition, it is not at all obvious that an English speaker would realize that feather is the word being defined. A different kind of problem affects cognitive and extensional GD defi nitions equally, in those cases where it is not clear that the definiendum does belong to any broader class. Self and time are two possible examples.

QUESTION Try and formulate a GD definition of these words. How do you define the genera you have used? QUESTION Can you think of other words for which a GD definition seems difficult? What causes the difficulty?

اخر الاخبار

اخبار العتبة العباسية المقدسة

شعبة التوجيه الديني النسوي تنظم مسابقة ثقافية بذكرى ولادة السيدة المعصومة (عليها السلام)

المجمع العلمي ينظّم محاضرةً تربوية لطلبة مشروع حفظ القرآن الكريم في كربلاء

قسم الشؤون الفكرية يقيم معرضًا وثائقيًا ضمن مهرجان (الشهيد) في جامعة الكوفة

قسم الشؤون الدينية يشهد إقبالًا واسعًا من المؤمنين لتنظيم عقود الزواج

المزيد

الآخبار الصحية

دواء جديد يحمي القلب ويعزز علاج السرطان في آن واحد

سر غذائي بسيط لحماية القلب مع التقدم في العمر

علامات تشير إلى اختلال عمل الغدة الدرقية

السمنة واللقاحات.. دراسة تكشف تأثيراً سلبياً

المزيد

الآخبار التكنلوجية

البعوض في آيسلندا إشارة مبكرة على تحولات بيئية في القطب الشمالي

صاروخ يطلق قمرا اصطناعيا في مدار خاطئ

"أوبن إيه آي" تطلق نموذجا للعلوم الحيوية واكتشاف الأدوية

تفوق على البشر.. روبوت يحطم الرقم القياسي لسباق نصف ماراثون !

المزيد

مواضيع ذات صلة

Definition and substitutability

non-compositionality

Compositionality

Meanings above the word level: idioms

Meanings below the morpheme: sound symbolism

Semantics and lexicography

Meaning and the dictionary

Meaning and explanation

Meanings as referents/denotations

Lexemes

Meaning in Chinese

Meaning in Warlpiri