the greatest possible number of units of good (as they relate to free choice). A multiverse that realizes every potential unit of good is a maximally good universe, one that a perfectly good and all-loving God would be compelled, or perhaps even required, to create.
Some may argue that even if God is required to create a maximally good universe and, even if it is also true that free will is the greatest possible good, we need not appeal to a multiverse model to reconcile the two. We could simply imagine one universe in which there are enough free agents actualizing enough free choices in order to exhaust and gain all possible units of good. Surely this would create a maximally good universe without the use of a multiverse. In response to an objection such as this, while there is no doubt that a single-universe model such as this would yield a good universe, perhaps one that satisfies proponents of a “threshold” model of greatest possible worlds, I am after a maximally good ontological view, and a single universe just cannot satisfy that since I would leave too many goods as potential rather than actual.
Another reason that a single-universe model would not satisfy the kind of maximal good that I am after is that no matter how good a particular universe may be, enjoying an enormously large number of agents who make a variety of free choices, such a universe could always be improved upon with the addition of one more freely acting agent. The addition of one more agent would result in, minimally, one more free choice being made by that agent, increasing the overall goodness of that universe. For any single-universe model, no matter how many agents there are, there could always be one more added to increase the goodness of that universe, and yet even with that addition of any arbitrary number of agents there would still be a multitude of unclaimed units of good because of the inability to actualize each possible free choice. The same cannot be said of the multiverse model outlined above since it, by its very nature, exhausts all possibilities of free choices as well as all possible combinations of free choices. So, yes, for any individual universe within the multiverse one more agent could be added to create a universe with more good in it, but such a universe already exists elsewhere in the multiverse. Having the existence of such a universe (with that added agent in it) means that the goodness is merely realized in another universe, yet still within the same multiverse, which is the scope on which the maximal goodness of concern ought to be measured.
For those who find it difficult to maintain that free will is the greatest possible good there are still several possible alternatives that could yield the existence of a multiverse. In the first alternative, it seems that we can substitute something such as happiness, joy, or pleasure for free will, and the multiverse account may still remain the same. Surely we can agree that there are different types of happiness, and failing that; there are at least different ways of attaining happiness.14 This being the case there would seem to be different kinds of happiness that are incompatible with each other, such as the happiness or satisfaction felt from eating the last piece of your favorite cake immediately, and the happiness or satisfaction felt from saving that same piece of your favorite cake for later and enjoying it after a period of anticipation. Assuming that the situations that we are talking about both involve the exact same person and the exact same piece of cake then it seems that enjoying both of these kinds of happiness is not possible since one cannot both be happy that he is currently enjoying the last piece of his favorite cake while simultaneously enjoying the anticipation of being able to enjoy his favorite piece of cake at a later time. Returning to the previous terminology of “units of good,” with each kind of happiness equating to one unit of good, then, in this case, only one unit of good could be recognized while the other is left as potential. In order to recognize both units of good and create a maximally good world (or multiverse), a second universe would be needed so that both kinds of happiness can be instantiated.
The same principle follows for a wide range of other goods such as for example, justice, existence, life, and so on. For each different good, it seems that within it there are multiple variations of that good that may not be compatible with each other, thus requiring a multiverse in order to realize all of them. While I will not go on into such detail as to provide examples, as I have done with free will and happiness, it stands that such an account is at least plausible and that for any good that is argued to be the greatest possible good a multiverse will be entailed by it.
Secondly, for those who do not want to maintain that there is a single greatest possible good, rather that there are a variety of inherent goods that are on-par with one another or that there is a greater goodness held in a variety of goods rather than a flood of one greatest possible good, this too could entail a multiverse. In this case, it is not altogether clear that there is a single instantiation of a variety of goods is any better than any other instantiation, and given the principle of plenitude, it still seems that God would create a multiverse in order to realize all possible combinations of goods. For example, it is not clear that a universe, universe A, whose maximal goodness is composed of 50 percent happiness, 30 percent justice and 20 percent free will is any better than another universe, universe B, whose maximal goodness is composed of 40 percent life, 25 percent pleasure and 35 percent honesty. Whether universe A is better than universe B or not, it seems that God would be obliged to create both of these universes, and a whole host more, since they are all on-balance good, and more of a good thing is a better thing. The universes that God would create would be ones that exhaust every possible composition of every inherent good that yields an on-balance good universe, thus resulting in a maximally good multiverse. Again, while the individual universes themselves will not yield maximal goodness, they comprise a multiverse that is maximally good.
The Scientific Case for the Multiverse
As with the case in philosophy, much work is going on in the sciences (primarily physics, for our purposes) regarding multiverse theories. Tim Wilkinson notes that “[a]t the coal force of science . . . it is usually extra-ordinarily difficult to find even one theory that fits the facts. In the current context, we do have a few competing theories, but all imply broadly the same thing: a multiverse” (2013, p. 94), meaning that while a survey of the literature seems to suggest that there is scientific consensus on the existence of a multiverse the debate arises in just what kind of multiverse we happen to be a part of. For the scientific community, according to Wilkinson, the question is not whether a multiverse exists, rather there are questions about the composition of the multiverse, the origins, the physical constants of the multiverse and the individual universes within it, and so on. Similar to the previous section and the treatment of philosophical discussions of the multiverse the following is a short introduction to several ideas within physics regarding the multiverse.15 While I do not generally go into detail regarding the methodology and justification for the various multiverse accounts presented (since they are typically quite complex and laden with mathematical jargon) I present the concluding prediction of each theory. The reason for including a section on the scientific perspectives of the multiverse, in this overall philosophical discussion, is twofold. In the first case, scientific approaches to the multiverse provide us with just that, a different approach, bringing to light different conceptions of the composition, formation, and general structure and nature of the multiverse. The second reason is that, while philosophical approaches to the multiverse may be logically consistent and conceivable, scientific approaches seem to have that extra level of justification given that they have to be not only logically consistent but physically plausible as well. That is to say; I think that any philosophical view of the multiverse, no matter how strong it may be, can be strengthened and given more credibility if it is supported by a scientific account of the multiverse.
Max Tegmark composed a paper that serves as somewhat of a survey paper, not of particular scientific theories of the multiverse, but of the different and more general types of multiverse theories available within physics (Tegmark, 2007). Tegmark argues that most (if not all) current scientific multiverse theories taken seriously propose or predict multiverses that fit into one of four distinct categories, or levels, as he calls them. Each level, beginning with level 1, progressively varies more and more (with regards to the physical constants, laws of nature, etc.) from our universe. Similarly, as the levels progress up from 1 to 4 the multiverse theories that fall under them become increasingly debated and less easily accepted. That is to say, level one is the multiverse model that contains
