You are a human being. But what if you were an oyster?

You are a (fe)male. But what if you were a different sex?

You exist. But what if you didn't exist?

You are of a certain race or ethnicity? But what if this were different?

All of these are examples of counterfactual thinking. It compares one state with another state.

However, how meaningful are these sorts of counterfactual statements? When are counterfactual statements actually descriptive and when are they fictional?

Two of the four, or perhaps even all four examples, are what I would deem to be meaningless counterfactuals. They are meaningless because identity is not maintained through the switch between the initial state and the final state.

For example, you are a human being. Being a human being is part of what makes you, you. If you were an oyster you wouldn't be you. So there's no point in talking about things like "what if I were an oyster?" because the fact is that you metaphysically cannot be an oyster without losing part or all of your identity.

The same applies to existence. You either exist, or you don't. You either exist as a human, or you don't exist at all. Predicating upon a non-existent entity is, from what I can tell, entirely fictional. When I do so I end up conjuring up some ghostly image of a sleeping entity that somehow exists in non-existence. Yet this is quite unreasonable.

If you doubt this, consider what would happen if there actually was some realm of non-existence where people's souls actually existed. Then we would actually be perfectly comfortable and justified in predicating upon these non-existent people, because they actually exist. Counterfactual statements for non-existence are simply a heuristic that is useful but fundamentally mistaken.

Sex changes and racial/ethnic changes are examples of things that may or may not allow you to successfully compare counterfactually. Changing my skin color may change how I act but it doesn't seem like it will change who I am as a person, as a psychological continuity. Changing my sex organs may change who I am based upon what chemicals are being pushed through my veins, and this may or may not change who I am.

So what is/are the requirement(s) for a successful, meaningful counterfactual statement? I think, at the very least, a meaningful counterfactual statement has to maintain the essential qualities of the subject. Asking what it would be like to be an oyster would thus be meaningless because essential qualities of human-hood would be lost in the transition from being a human to being an oyster.