In recent decades, there has been tremendous growth in scientific theories which postulate the existence of many universes beyond our own. Once considered absurd, multiverse theories now appear to be gaining considerable scientific respectability. That said, the details and implications of each one are hotly contested by physicists and cosmologists.

In the philosophy of religion, multiverse theories are most frequently discussed in connection with the fine-tuning argument for the existence of God. In its simplest form, this argument runs as follows. If certain features of the universe had been slightly different, the universe would not have been capable of generating and sustaining life. This apparent “fine-tuning”, some say, is best explained by positing an intelligent designer. Critics have countered that multiverse theories undermine this argument. If there are vastly many universes which vary – perhaps randomly – in their relevant parameters, they say, then it is not at all surprising that at least one universe is life-permitting. In this debate, then, multiverse theories are typically offered as naturalistic rivals to theism.

Yet, in a surprising twist, several philosophers have recently offered various reasons for thinking that, if theism is true, there are many universes. Rather than being deemed rivals to theism, then, multiverses are here deemed to be consequences of theism. Moreover, some philosophers have argued that a theistic multiverse model can even help to defend theism against prominent arguments for atheism, including the problem of evil and the problem of no best world. All of these claims are controversial, and a body of literature has recently developed around them.