Vikram — here is how I understand your argument. First, there are two types of detachment — detachment from the results of action, and detachment from purpose.

The first, detachment from action, is not the entire story — for Krishna urges Arjuna in the Gita not to be detached without purpose. Furthermore, purpose, which implies a goal, which in turn implies a plan, must be in alignment with dharma. 

The Joker’s quote (“If you’re good at something…”) as well as the fact that one cannot be attached to fruitive action and simultaneously detached from purpose imply that, if we define detachment this way, the Joker is not completely detached.

That is my understanding of your interpretation, which establishes that the Joker is not detached.

I am confused about some terminology. Your interpretation contains three key words:

1. detachment
2. action
3. purpose

The definition of detachment we can both agree on — something like what Merriam-Webster says, “indifference to worldly concerns.” That is done.

The difference between action and purpose is more challenging. You start your argument by saying that action and purpose are in fact different. 

To discuss action, which is easier to define than purpose — your statement makes me initially consider an action as a mind’s unbroken string of concentration. For example, going downstairs is an action. But an objection to this definition is that doing something else while going downstairs invalidates this definition, for the mind cannot concentrate on two things at once. To address this objection, I suggest that the mind can in fact concentrate on two things at once if the mind considers one a habit. In this case, going downstairs is a habit, and thinking is an action requiring an unbroken string of concentration. So let us say, for the sake of discussing the issue, that an action is a mind’s unbroken string of concentration or habit. Like detachment, action is now defined.

Purpose, on the other hand, is a harder word to define than “action,” especially since the way it is defined will either make or break what you are trying to say. For if purpose is itself an action that manages other actions, then by definition there can be no distinction between action and purpose, and hence no distinction between detachment from either.

So how are we to define purpose? I want to make sure I understand what you are saying, so I think it is best if you describe your definition.