Carroll was talking about that emotion is directed at some object in Horror and Humor as below:

Emotions are mental states; they are directed. They are intentional states. They must be directed at objects, real or imagined. In order to be in love, I must be in love with someone. In order to be afraid, I must be afraid of something. An emotion is a mental state that takes or is directed at some object. An emotional state is not merely a feeling state, thought it involves feeling. An emotional state involves a feeling that is related to some object.

His argument is clear, but I somehow feel that the logic is not quite clear, even though he has provided the example of the drug that can replicate anger. Never mind. John Dewey has talked about the same thing in the third Chapter of Art as Experience:

By the same token, emotions are attached to events and objects in their movement. They are not, save in pathological instances, private. And even an “objectless” emotion demands something beyond itself to which to attach itself, and thus it soon generates a delusion in lack of something real. … In order to become emotional they must become parts of an inclusive and enduring situation that involves concern for objects and their issues.

I suppose Dewey wrote his article before Carroll, and I wonder whether Carroll knows that Dewey has similar argument here. That can be interesting.