On Anselmian theism (AT), God is, amongst other things, a necessary being. On genuine modal realism (GMR), possible worlds are maximal mereological sums of spatiotemporally connected individuals. I argue in this paper that AT and GMR are either incompatible or their conjunction leads to-amongst other things-modal collapse. Specifically, I argue: regardless of whether God is concrete or abstract, His necessary existence either is inconsistent with AT-GMR or it leads to, amongst other things, modal collapse for AT-GMR. I conclude the paper by contending that, if I am correct, the ATist will have an argument against the truth of GMR, and the GMRist will have an argument against the truth of AT.

Lewisian theism is the view that both traditional theism and Lewis’s modal realism are true. On Lewisian theism, God must exist in worlds in one of the following ways: (1) God can be said to have a counterpart in each world; (2) God can be said to exist in each world in the way that a universal can be said to exist in worlds (if universals exist), i.e. through transworld identity; (3) God can be said to be a scattered individual, with a part of God existing in each world; and, (4) God can be said to exist in each world, through His existing from the standpoint of each world. In the literature, (1)–(4) have been rejected as viable options. I grant that (1) and (3) are not viable. However, I believe that (2) and (4) have been too hastily rejected. Herein, I develop ways to respond to objections to (2) and (4), and conclude that (4) is a viable option for Lewisian theists.

Emily Paul has recently argued that Brian Leftow’s account of why the import of God’s becoming Incarnate is not temporal but modal fails. She argues that Leftow’s required modal variation is not satisfied. That is, we do not have the required variation across logical space concerning the Incarnation. Paul examines her argument on two possible worlds theories: theistic ersatzism and (what I call) Lewisian theism. She thinks that both possible worlds theories face difficulties. I argue that Paul fails to provide a compelling argument against Leftow because, firstly, her defence of one her premises fails, and, secondly, she misjudges what is required for some of Leftow’s claims to be true. I also argue that some of the problematic consequences that Paul raises for theistic ersatzism and Lewisian theism either are not problematic or can be avoided.

Yates has recently argued that modal dispositionalism invalidates the (T) axiom. Both Yates and Allen have advanced responses to the objection: Yates’s response proposes installing truth into the possibility biconditional, and Allen’s response requires that all properties be construed as being essentially dispositional. I argue that supporters of Borghini and Williams’s modal dispositionalist theory cannot accept these responses, given critical tenets of their theory. But, since these responses to the objection are the most plausible in the literature, I conclude that the threat that Borghini and Williams’s modal dispositionalist theory invalidates the (T) axiom still looms large.