productivity of thought
Thought is said to be productive, since, in a sense, normal cognitive agents are capable of having denumerably many distinct thoughts. In other words, to say that thought is productive means that normal cognitive agents have the competence to entertain denumerably many distinct thoughts

Jerry Fodor and Zenon Pylyshyn have used the putative productivity of thought as part of an argument for the view that there exists a mental language of thought with syntactic and semantic atoms that may be composed to form syntactic and semantic molecules and that cognitive processes are causally sensitive to this syntactic and semantic structure. If an agent can entertain denumerably many thoughts, then a finite agent must have the resources for representing denumerably many thoughts. Such resources consist of a finite stock of atomic representations along with the means of recursively composing them into arbitrarily large molecular representations.
Ken Aizawa