“Truly, all we know of good and duty proceeds from nature; and none the less so all we know of evil. Visible nature is all plasticity and indifference, – a moral multiverse, as one might call it, and not a moral universe.” – William James, Is Life Worth Living?1
We might reasonably expect cosmologists to assert that the universe is the ultimate structure in reality, but it turns out that many experts believe that our universe may be merely one of many or even an infinite number of universes. In effect this more expanded notion of the cosmos, known as the multiverse, includes unimaginable numbers of universes of different sizes, ages, and physical laws akin to holes in a piece of Swiss cheese. Of course, we cannot observe other universes, confined as we are in our own, but there are four surprisingly strong arguments for their existence.
First is the ‘fine tuning argument.’ Scientists know that even small changes in a few fundamental constants or physical laws in our universe would have made stars, planets, and life impossible. It appears naïve to say that our universe just happened to be conducive to our existence, and as such this improbability serves as the basis of the modern cosmological argument for the existence of a deity who presumably made sure the universe would comport with intelligent life. The more satisfactory scientific argument however is that there are many universes and of course we must be in one of those which permits life in order for us to exist to wonder about it; a stance known as the anthropic principle.
The second argument for the multiverse is its ability to explain what existed before the Big Bang origin of our universe. By this reasoning the multiverse is eternal and our universe like so many others began in a Big Bang event arising most likely from another universe. This explanation gives us the best of both worlds – our universe has a finite life dating back to the fairly well established Big Bang, while the multiverse has no creator, instead an infinite history.
The third argument is a consequence of quantum physics, that is the theory that our universe arose spontaneously in the quantum vacuum. Presumably in the timelessness of quantum space, if one universe can appear spontaneously, there should be an infinite number of instances of like ‘creation’ making ours not the only universe, but one among an infinitude. In short if the quantum physicists are correct that we can get a universe from nothing, then there should be an unlimited number of them.
The final argument is based on string theory and complicated. Einstein showed that the universe is a huge expanding bubble. If the string theory is correct, and it is the best current theory for the nature of matter, than there are 10 or more dimensions and a multitude of string equations that can describe versions of reality. Michio Kaku explains the implication: “String theory indicates other bubbles out there, each a solution of the string equations. In fact there is a bubble bath of universes, creating a multiverse.”2 Many of these are microscopic and short-lived, but in total they would make up Steven Hawking’s ‘space-time foam.’
(continued next post)
1This passage represents the first known use of the word, ‘multiverse’ (bold in the quote is mine).
2Kaku, Michio, The Future of Humanity, Anchor Books, New York, 2018. ISBN 978-0-525-43454-2, page 300.