"We are all one" is a common expression. "We're all interconnected," my mom used to say. "We are all part of each other," proclaim the god-like beings in one of my childhood movies, The Dark Crystal. These sentiments are fairly common throughout history, as you can see from the open individualism Wikipedia page.

I personally subscribe to empty individualism rather than open, but I think the distinction isn't that important ethically. In either case, the results are pretty similar. In particular, with empty individualism, you see your future self as one more organism that will have feelings, but it's not really different from any other present or future organism that will also have feelings. So why worry more about your future self than other selves? With open individualism, you see other selves as part of yourself, in which case you care about them as much as you care about your future self.

I vary in the extent to which I intuitively internalize these individualism-dissolving feelings. Many times my utilitarian motivations come from regular "empathy for others as others" rather than "caring about others because they're like myself." I think empty/open individualism are not necessary for utilitarianism. But they can be motivating for some, and they might be an interesting avenue to pursue.

I personally subscribe to empty individualism rather than open, but I think the distinction isn't that important ethically.

I don't think so. As long as you are an altruist, you are right. If you act out of "empathy for others as others" rather than "caring about others because they're like myself" there is really no difference.
But if "you" would be a more "egoist" supporter of empty individualism "you" wouldn't care about the future at all, even about "your" own because "you" wouldn't exist then.
If you are an open individualist, you surely would care about the future of everyone as they all are you.
Personally I cannot imagine open individualism. I simply lack the empirical evidence for that. I did never experience that other people were me. There are people who have had spiritual experiences in which they felt connected to everything. I think, this really helps to care more about "others" and as far as it doesn't lead to loss of reality, these experience can be really useful and important to the world.

Maybe we should start a discussion thread on the necessarity of artificially inducing spiritual experiences.

Brian, I've heard the phrase 'empty individualism' before, but never found anything online that defines it. Is it just another name for what David Chalmers calls the deflationary view of personal identity?