There are plenty of sentences that have a noun, a verb, and a subject without having an agent—anything in passive voice or any unaccusative will do the trick. I suspect the argument would be even better worded using semantic roles rather than syntactic categories, eg: “Causality exists when there is an event with an agent”. This isn’t a very interesting thing to say though, because “agent” is a casual semantic role and so relies on causality existing by definition. You literally cannot have an event with an agent unless there is causality.
There are plenty of sentences that have a noun, a verb, and a subject without having an agent—anything in passive voice or any unaccusative will do the trick. I suspect the argument would be even better worded using semantic roles rather than syntactic categories, eg: “Causality exists when there is an event with an agent”. This isn’t a very interesting thing to say though, because “agent” is a casual semantic role and so relies on causality existing by definition. You literally cannot have an event with an agent unless there is causality.
Yes, agreed. Semantic roles make the claim much more valid (but also less interesting, it seems to me).