# 1-, 2-, and 3-place predicates

Would the following verb be a one- or two-place predicate verb?

"The boy and his friend left"

I'm inclined to think that it's a one-place predicate as normally 'leave' is just that, and that 'the boy and his friend is the subject of the sentence and is counted as a single 'entity' (??) if that makes sense.

Also, can verbs be differently numbered predicates depending on contexts?

eg. donate -> he donated his money => 2-place predicate

but he donated his money to her => 3-place predicate?

I'm aware there's already a similar question about one- and two-place predicates, but I just wanted to clarify specifically.

• The boy and his friend is a compound subject. A predicate has to have a verb and state something about the subject. So, they left, one predicate; The boy and his friend left the building and crossed the parking lot on their skateboards.=two predicates. Commented Oct 26, 2023 at 14:57

## 1 Answer

The idea that verbs are "1- /2- etc. place" predicates derives from predicate logic. It says that such predicates are functions (in the mathematical sense) that take a defined number of arguments in order to deliver a value, in this case the value (the outcome) is a logical proposition which may then be true or false.

The idea that verbs can be taken to be logical predicates of this kind is a scientific theory, a theoretical model. The idea is strictly speaking true of the theoretical model, not directly of the verb. Verbs in natural language are fairly flexible, their meaning can appear in different nuances, and the number of grammatical arguments may vary accordingly. The logical calculus does not provide for anything like this, so this is a point where linguists start tinkering with the theory. So you can be relaxed about a verb being a 1-place predicate or not, they will usually be flexible and therefore correspond to different logical predicates.

The type of argument that a verb takes is a different matter. In linguistics, different sorts of entities are distinguished, and single "individuals" or "groups" are two different examples of entities. So a one-place verb may take an individual or a group as its argument, but it remains 1-place because in the logical model, only one step is needed to convert the predicate into a sentence. (This is the case in your example with "leave").

An example of flexibility is that some verbs alternate between 1 and 2 places, for example: "[The car] collided with [the tractor]" or "[The car and the tractor] collided." The second example is technically a 1-place predicate, but has a group as its subject. In the first example, the members of this group are distributed over 2 argument positions. The logical predicates here are of different type, the natural language meaning is not so much different (it's just that in the 2-place version, the object may be more passive).

• The relation between a verb and its potential subjects is general and lends itself to many generalizations. On the other hand, the relation between a verb and its objects, if any, is extremely specific, to the point that the restrictions, requirements, and possibilities of its selectional restrictions constitute part of the meaning of the verb. For a simple instance, English steal, rob, and rip off, while they can describe the same event, differ in their object options. Commented Oct 27, 2023 at 14:43
• Yes, but the specific type of meaning relation between verb and object, as opposed to subject, is exactly what the purely formal distinction "1-/2-place" does not take into account. -- Btw. steal and rob do not denote the same events. Commented Oct 29, 2023 at 14:32
• They need not, especially as metaphors, but they certainly can report the same event, just as murder, kill, and assassinate can report the same event (though not with the same pragmatics). Commented Oct 29, 2023 at 16:38