Categorising Definitions

Alongside avoiding emotional investment in ideas, semantics is one of the most difficult parts of philosophy, because agreeing on the names of things is not simple. Language is a social process, and each actor in that process needs to agree for a word’s meaning to have authority: there needs to be a consensus.

Complicating things is the fact that many words have multiple definitions, and in philosophy this can be especially problematic, where a word such as “realism” can have about twenty different meanings. Frankly, this leads to information overload and ambiguity, and therefore misunderstanding. In the words of Socrates (maybe):

The beginning of wisdom is the definition of terms.

So, allow me to present my understanding of both the foundations on which definitions rest, and the functions that they serve. Importantly, I will also discuss the truth of a definition, which varies according to its function. Hopefully this will allow us to reduce future confusions, and correspondingly think more clearly. After all, we all have a part in shaping our common language, and the way we think directly affects the words we choose to use.


Empirical definitions

These are simply where a label is attached to something perceptible; it could be an object or a phenomenon. This includes ostensive definition, “definition by pointing”. This is just a case of providing real examples that fit the label.

It’s called plasma. (Luc Viatour, CC-BY-SA)

Another way of defining something empirically is through an operational definition, where a word is defined with respect to an experimental or procedural “recipe”. This is quite common in the social sciences particularly, where phenomena such as “anger” are difficult to observe without particular conditions being met.

A jam sandwich is that which results from taking two slices of bread and spreading jam between them.

A definition can only be more or less operational, because ostensively defined concepts must enter into the equation – it is impossible to provide a recipe without an already-understood language.

Theoretical definitions

These are where a concept is labeled with respect to other, already-defined concepts, as a node in a theory. This is usually a logical relationship, given by a binary or mathematical operator.

Force is the product of mass and acceleration.

Theoretical definitions can even involve recursive definitions, where a concept is defined with respect to itself.

An ancestor is either a parent or the parent of another ancestor.


Definitions can broadly be classified by whether they function to describe the language, or to prescribe it; that is, a definition is either inferred from, or imposed upon the language.

Descriptive definitions

A descriptive, or lexical definition reports how a word is actually used.

1. The act of destroying.
        The destruction of the building will take place at noon.
2. The results of a destructive event.
        A flower bloomed amid the seemingly endless destruction.

Often there will be many meanings or senses to the one word; this is known as polysemy. This fact can introduce ambiguity, which can represent a barrier to clear reasoning. The truth of a lexical definition is an empirical matter; the question is simply, “Is the word really used in that way?” Dictionaries such as Wiktionary have their own policies on the criteria for inclusion which stipulate precisely what really used means.

Prescriptive definitions

Some definitions function prescriptively, to change the language by suggesting new words or changing their meaning. When a new word is proposed, this is called a stipulative definition, and is inherently a creative process. Because stipulative definitions are essentially about labelling the world, they are necessarily true to the author as soon as they are defined (truth is about correspondence to experience). If I wanted to call my computer a “zash”, it would become true to me that I am typing on a zash. However, until they are accepted and used by a wider community, these definitions remain meaningless to others. Any dictionary that included “zash: a computer” would be wrong, because one person (me) does not constitute a linguistic community. An example of a stipulative definition is found in Heidegger’s writing:

“This entity which each of us is himself…we shall denote by the term “Dasein”” (Heidegger, trans. 1927/1962, p.27).

One type of stipulative definition is where a term is defined with the specific aim of reducing ambiguity, especially for applications where this would be a problem, such as legal terminology or academic discourse. This type of stipulation is known as a precising definition, or more commonly as jargon.

For the purposes of driving in Australia, “intoxicated” means having a blood alcohol content at or above 0.05 percent.

The meaning of a precising definition is specific to its context. “Is it true that “intoxicated” means having a blood alcohol content at or above 0.05 percent?” Well yes, in this document it certainly is. You might debate the utility of that definition, but the author has laid down an assumption which must be taken as fact before evaluating their arguments. And this definition might represent the consensus of a whole institution, so it becomes a fact within that institution.

A specific type of precising definition is the emotive definition, where a word is defined to represent the moral and aesthetic biases of the author.

Abortion is nothing more than the slaughter of fetuses.

Other writers often refer to these as persuasive definitions, but I prefer the term emotive, because ultimately, emotive language (as opposed to neutrality) is what characterises them, and I do not find them very persuasive let’s call a spade a spade.

Of course, all stipulative definitions reflect the biases of their authors, and there is an inherent forcefulness to them. But to the extent that neutral language is avoided, a definition remains emotive and is very unlikely to enter general parlance.

It is also worth noting that choosing not to use a term is a prescriptive definition of sorts; if enough people do it, it redefines a once-used word to meaninglessness.


As English speakers we are the inheritors of a wealth of words by which to describe our world, and that is, of course, wonderful. However, it is sometimes necessary in the course of thinking to redefine a concept, or narrow its meaning, to aid in the clarity of thought. Occasionally we even need to coin new words! Providing good reasons for your decision is the best way to make it stick with other people, and that is ultimately the way new concepts propagate. For example, I actively avoid using the word “realism”, in protest of its ridiculous overuse and resulting ambiguity. Perhaps you agree and the language will slowly change. In the meanwhile, thank you for reading!


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