One of the fundamental questions shared by science, philosophy and theology is the question of why the universe is the way it is. Over the centuries, the answers have fallen into two broad camps. The first is that of teleology. This is the view that the universe is the way it is because it has a purpose, goal or end for which it aims. The second is the non-teleological camp, which is the denial of the teleological view. Members of this camp often embrace purposeless chance as the “reason” why things are as they are.
Both camps agree on many basic matters, such as the view that the universe seems to be finely tuned. Theorists vary a bit in their views on what a less finely tuned universe would be like. On some views, the universe would just be slightly different while on other views small differences would have significant results, such as an uninhabitable universe. Because of this apparent fine tuning, one main concern for philosophers and physicists is explaining why this is the case.
The dispute over this large question nicely mirrors the dispute over a smaller question, namely the question about why living creatures are the way they are. The division into camps follows the same pattern. On one side is the broad camp inhabited by those who embrace teleology and the other side dwell those who reject it. Interestingly, it might be possible to have different types of answers to these questions. For example, the universe could have been created by a deity (a teleological universe) who decides to let natural selection rather than design sort out life forms (non-teleological). That said, the smaller question does provide some interesting ways to answer the larger question.
As noted above, the teleological camp is very broad. In the United States, perhaps the best known form of teleology is Christian creationism. This view answers the large and the small question with God: He created the universe and the inhabitants. There are many other religious teleological views—the creation stories of various other cultures and faiths are examples of these. There are also non-religious views. Among these, probably the best known are those of Plato and Aristotle. For Plato, roughly put, the universe is the way it is because of the Forms (and behind them all is the Good). Aristotle does not put any god in charge of the universe, but he regarded reality as eminently teleological. Views that posit laws governing reality also seem, to some, to be within the teleological camp. As such, the main divisions in the teleological camp tends to be between the religious theories and the non-religious theories.
Obviously enough, teleological accounts have largely fallen out of favor in the sciences—the big switch took place during the Modern era as philosophy and science transitioned away from Aristotle (and Plato) towards a more mechanistic and materialistic view of reality.
The non-teleological camp is at least as varied as the teleological camp and as old. The pre-Socratic Greek philosophers considered the matter of what would now be called natural selection and the idea of a chance-based, purposeless universe is ancient.
One non-teleological way to answer the question of why the universe is the way it is would be to take an approach similar to Spinoza, only without God. This would be to claim that the universe is what it is as a matter of necessity: it could not be any different from what it is. However, this might be seen as unsatisfactory since one can easily ask about why it is necessarily the way it is.
The opposite approach is to reject necessity and embrace a random universe—it was just pure chance that the universe turned out as it did and things could have been very different. So, the answer to the question of why the universe is the way it is would be blind chance. The universe plays dice with itself.
Another approach is to take the view that the universe is the way it is and finely tuned because it has “settled” down into what seems to be a fine-tuned state. Crudely put, the universe worked things out without any guidance or purpose. To use an analogy, think of sticks and debris washed by a flood to form a stable “structure.” The universe could be like that—where the flood is the big bang or whatever got it going.
One variant on this would be to claim that the universe contains distinct zones—the zone we are in happened to be “naturally selected” to be stable and hospitable to life. Other zones could be rather different—perhaps so different that they are beyond our epistemic abilities. Or perhaps these zones “died” thus allowing an interesting possibility for fiction about the ghosts of dead zones haunting the cosmic night. Perhaps the fossils of dead universes drift around us, awaiting their discovery.
Another option is to expand things from there being just one universe to a multiverse. This allows a rather close comparison to natural selection: in place of a multitude of species, there is a multitude of universes. Some “survive” the selection while others do not. Just as we are supposed to be a species that has so far survived the natural selection of evolution, we live in a universe that has so far survived cosmic selection. If the model of evolution and natural selection is intellectually satisfying in biology, it would seem reasonable to accept cosmic selection as also being intellectually satisfying—although it will be radically different from natural selection in many obvious ways.