I see what you mean about all possible things existing on your account.

I then move to,

“My concern about non-existence is not fully captured by a supposed fear of inter-world travel”

When I worry about whether or not will I exist (worry A) I do not worry that I will cease to be positioned in this world (worry B).

My not being positioned in this world does not entail that I am not positioned in any world.

While I may prefer this world to other worlds (all my stuff and friends are here) it would still calm my fear to know that I will be positioned in some world. Worry A is more accurately the fear that I will not be in any place/world.

To this you may reply that it is an irrational fear because I will remain possible, and so will always be in some world (maybe you will appeal to counter-parts for this). Yet, this reply would miss the mark precisely because worry A is not that I will cease to be in a domain of quantification, but that in any given domain I shall lack the property of existence.

Well, be careful here… are there coherent things which are not even possibilia? If all coherent things are possible, then these things exist on my suggested account. My suggestion is that the worry you point to is not one about existence at all, but one about what ‘actually exist’ vs. ‘merely possibly exist’.

“My concern about non-existence is not fully captured by a supposed fear of inter-world travel”

I’m not sure what you are getting at here. Could you say more about your feat of non-existence, maybe that will clarify for me the force of the point.

Thank you for the comment. You make some good points. I reply as follows:

1. I do worry about whether or not square circles exist because dialetheism makes me uncomfortable.

2. My understanding of Lewis’ modal realism is that the actual world is determined indexically – i.e. the actual world is this world.

It would then seem to follow that I exist in the actual world necessarily if only I am possible and existence is synonymous with actuality. Yet, there are many things that are coherent but which do not exist.

There may be an ambuiguity here between ‘actual world’ at the time I am considering future possibilities, and ‘actual world’ at the future time. However, the point remains that the thing that I am truly concerned about is not equivalent to concern about which world I will occupy. My concern about non-existence is not fully captured by a supposed fear of inter-world travel.

If, as against this, we try to give the actual world some ontological priority over other merely possible worlds then I would say that we are then merely hypothesizing that all things with the property of existence are to be found in the actual world, and all other worlds and their contents do not exist. That would be fine by me. It would imply nothing more than that we define the actual world as the set of all existing things.