| • Science | • People | • Locations | • Timeline |
| Contents | ||
There is a general name for the first two sorts of error: circular definition. A circular definition is somewhat similar to a question-begging argument: neither offers us enlightenment about the thing we wanted to be enlightened about.
A definition is no good if it simply gives a one-word synonym. For example, suppose we define the word ' virtue'--an important word in ethics--just using the word 'excellence'. It might be perfectly true that all virtues are excellences and all excellences are virtues (that was perhaps an ancient Greek view; see arete), but the word 'excellence' by itself is not a good definition of "virtue," in philosophy. One can always simply ask, "But what does 'excellence' mean?" Surely, if one has a basic confusion about what 'virtue' means, then one will also have a basic philosophical confusion about what 'excellence' means. So it will not do to define one simply by stating the other.
A definition is no good if it uses a very near synonym in the definition. For example, suppose we define ' beautiful' as 'possessing aesthetic value'. The words 'beautiful' and 'aesthetic' are very nearly the same in meaning; so if anyone is deeply confused or curious about beauty, then they are of course going to be confused or curious about the aesthetic. The question is what general characteristics are possessed by all beautiful objects, or all objects that have aesthetic value.
Definitions can be too broad. Suppose we define ' bachelor' as 'unmarried male'. On first glance this might look all right, but it applies to a lot of things, for example, male dogs, and male babies, that, needless to say, are not bachelors. A definition is too broad if it applies to things that are not part of the extension of the word defined. To correct this fallacy, narrow the definition. In this case, 'bachelor' can mean 'unmarried man'.
Definitions can be too narrow. That is, they can exclude some things that they should apply to; they fail to describe some members of the word's extension. Here is an example of a narrow definition: 'piece of furnitureFurniture is the collective term for the movable objects which support the human body (seating furniture and beds), provide storage, and hold objects on horizontal surfaces above the ground. Storage furniture is used to hold or contain smaller objects suc' means 'object used to sit on'. Of course, some pieces of furniture are not used to sit on; for example, we put objects on them (like tableTable can refer to several topics: Table (furniture) Table (verb) in a legislature Mathematical table Table (information), including spreadsheets, etc. Truth table Table (programming) How to use tables.s) or we put our feet on them (like footstool s), and so forth. So even though some pieces of furniture are objects that are used to sit on, not all furniture is used to sit on. We need a broader definition: we might add other qualifying characteristics, like 'used to put feet up on' or 'used to put household objects on', for example. That would make the extension of the definition bigger--that is, the definition would apply to more things, and more of the things that we use the word 'furniture' to describe. We might also choose to entirely rewrite the definition, since laundry lists of characteristics strung together by 'or' are generally regarded by philosophers as not describing a unitary concept.