Philosophy 220A: Symbolic Logic I
Department of Philosophy
University of British Columbia
Names, Predicates, Identity and Functions
Names and Predicates
The term ‘atomic sentence’ applies only to sentences of FOL (First Order Logic).
cannot really talk about an English sentence being atomic.
But here’s an English
sentence that is easily translated into an atomic sentence of FOL:
John Donne was a poet.
The first thing to note about this sentence is that the two main parts, ‘John Donne’ and
‘poet’ have very different kinds of meaning.
For the meaning of ‘John Donne’ is a
, a certain man who lived in England in the 17
The word ‘poet’,
on the other hand, has no such meaning, for there have been many poets.
point at John Donne, but you cannot point at poet.)
sentences, which means that they break them down into smaller parts.
In analyzing a sentence, the first thing to do is identify all the
, that it contains.
An individual constant is a word, or sequence of words,
whose meaning is some single, particular object, such as John Donne.
following are all names, or individual constants:
The Lions Gate Bridge
Note that some objects in the world have no individual constant (in English, at least), and
others have more than one name.
The same is true of FOL, which can have multiple
names for one object and no name for another.
One difference between FOL and English
is that FOL cannot have any names (like ‘Zeus’) that have no objective meaning, i.e.
which don’t refer to anything real.
Once all the names in a sentence have been identified, the analysis proceeds by removing
it (or them) from the sentence, leaving a hole (or holes) behind.
Thus the above sentence
…………… was a poet.