Ultimate Explanations of the Universe (13 page)

Are we not perhaps being too anthropocentric ourselves in our discussion on the anthropic principles? Can we not imagine a different biology than the one which has grown up on our planet? Perhaps we do not want to admit the idea (or maybe it just doesn’t occur to us) that there might exist an atomic physics governed by an equation other than the one discovered by Schrödinger? And maybe that is why the multiverses we are conjuring up are too close to our own measure?

Such deliberations are, of course, highly speculative, but their aim is to throw light upon the equally speculative notion of the existence of “parallel worlds.”

Nevertheless I would not like to go to the other extreme and deny the multiverse idea any cognitive value. Strictly speaking, the concept does not meet the criteria of science, since by very definition we have no experimental control whatsoever over other worlds, and the chances of indirectly testing their existence are negligible and based on probabilistic speculation. But the history of science teaches us that the hard core of science has always been enveloped by a ring of more or less philosophical speculations which have often played a heuristic role, suggesting valuable ideas and encouraging progress in previously unexpected directions. Today the concept of the multiverse is performing a similar role, which will be fulfilled to an even higher degree if the creative imagination is combined with rational criticism.

The anthropic principles force you to think. And they do so with a tremendous power of persuasion. The extremely precise fit of human existence into the structure of the universe is surprising at first, but after a while suggests various responses. The first thing that comes to mind is the principle of purposefulness. How did the initial conditions know how to fine-tune in order to make our existence possible? With such a high level of fine-tuning, the probability of a random occurrence seems negligible (in addition, for some people the idea that they exist by random chance is repugnant). Purposefulness is associated with the teleological argument for the existence of God. And indeed, the concept of the Grand Designer soon cropped up in discussions on the anthropic principles. But the Positivist and Empiricist traditions in the philosophical environment attending science were still too strong for that concept not to come up against a firm confutation. If there exists an infinite (or at least sufficiently large) number of universes fulfilling all the possible combinations of initial conditions, physical constants and other cosmological parameters, then it is no wonder that we live in a very special, life-friendly universe, since we could not have come into existence in any other universe. Therefore there is no random occurrence and no need to assume a Designer.

There is another option: simply to accept the message of the anthropic principles. And even make it as sharply defined as possible: Man did not come into existence because the universe was as it was at its origin, but the universe is as it is because Man exists in it.

Thus we have three philosophical attitudes to the collection of issues posited by the anthropic principles. They may be summed up by keywords: Designer, Multiverse, Man. We shall look at these three groups of issues, but in a different order. We shall start by presenting two views (Wheeler’s and Hawking’s) on the Man – Multiverse coupling, and examining the problem of human individuality in the context of Man’s potential existence in multiple copies in an infinite multiverse. Next we shall make a few observations on the subject of “Designer or Multiverse?” (though a fuller treatment of this will come in Part III), and only then, in the next chapter, will we attempt an evaluative review of the entire collection of ideas on the multiverse.

John Archibald Wheeler was well-known for his “crazy ideas.” Some of them developed into worthwhile research programmes and brought him fame. Whenever any of his ideas led up to a dead end, he would abandon it and think up a new one. Wheeler was not afraid of attacking the most difficult problems. For a long time he’d been looking for physical processes which could … call the universe into existence. But of course all processes are part of the universe, so they would have had to call themselves into existence. The wheel must come full circle. An opportunity opened with quantum mechanics, or rather its Copenhagen interpretation. According to this interpretation, certain properties of quantum objects (e.g. their spin, location, momentum…) do not exist until they are measured. It is the act of measurement or observation that calls these properties into being. Prior to the act of measurement a quantum object (e.g. an electron) can only be assigned a probability of being in a certain location, or of having a certain momentum. The object only acquires a given location or momentum once the measurement is carried out. Could it not be a similar case with the existence of the universe? Perhaps all the properties of the objects in the universe, together with the very existence of the universe, are only called into being by acts of observation carried out at a particular moment in the history of the universe. In other words – the universe did not have the property of existence until it was observed by a conscious observer.
¹

Wheeler was well aware of the tremendously speculative nature of his assumption, but that did not stop him from taking the idea further. A single act of observation (measurement) was required to call a particular value of an electron’s momentum into existence; but perhaps to call the universe into existence required observation by all the conscious beings in the universe. Wheeler called this kind of universe a “participatory universe.” Presumably this should be understood to mean that Man and the universe do not exist independently of each other, but mutually participate in each other’s existence and mutually condition each other.

Unlike many other ideas generated in the discussions on the anthropic principles, Wheeler’s speculations did not give rise to any new research models or projects. They simply remained as speculations not very closely connected with cosmology. Nonetheless they show how far ambitions to discover the ultimate explanation of the universe can go.

However, the idea of self-creation of the observer – universe system has recently re-emerged quite out of the blue in discussions on cosmology. It happened thanks to Stephen Hawking with no overt reference to Wheeler’s earlier ideas.
²
Hawking, in collaboration with Thomas Hertog, simply returned to his old quantum model of the creation of the universe out of nothing (see Chap. 7). As we recall: Feynman’s method of integration over paths allows us to calculate the probability of the transition of a quantum system from state
S1
to state
S2
, by computing the action integral over all the possible paths between these two states. Hartle and Hawking brought this method into cosmology, replacing the states of the quantum system with states of the universe, and all the possible paths joining those states with all the possible histories (geometries) from the
S1
state of the universe to the
S2
state of the universe. By performing a clever move they eliminated state
S1
(for details see Chap. 7) and calculated the probability of the universe emerging into state
S2
out of nothing (if there is no state
S1
).

Now let
S2
be the state of the universe we are now observing by means of our latest telescopes and space stations. “In the beginning” the universe was a quantum object; therefore there exists an infinite number of histories joining that “beginning” with its current state
S2
. In accordance with the method of integration over the histories adapted for cosmology and interpreted in the spirit of the Copenhagen interpretation of quantum mechanics, it is the act of observation that defines the history which has led up to
S2
, the currently observed state of the universe. And that very same act of observation has made all the other histories “extinguish themselves.”

In Hawking’s opinion, it is not a case of the history of the universe which began 13.7 billion years ago leading up to our existence; instead, the observations we are conducting now are selecting our history. The universe and the observer (mankind) are in a “causal loop.” Hawking reassures us: this kind of violation of ordinary causality occurs only when we are looking at the universe from without, from “the divine perspective.” But from our own perspective, the viewpoint of creatures immersed in the universe, it all looks exactly like what we are used to: we see the current state of the universe and think that it is the outcome of a single history which has occurred and which we are able to reconstruct.

It’s certainly a fascinating vision, but we should look at it from a critical distance. It is based essentially on the Hartle-Hawking model, and all the critical remarks and objections raised against that model at the end of Chap. 7 apply to this idea as well. Moreover, Hawking’s latest hypothesis is a substantial generalisation of his earlier model, which makes it even more vulnerable to criticism: a generalisation of a shaky hypothesis tends to be even shakier.

We should also realise that Hawking’s idea queries the entirety of the scientific method as practised hitherto. The fundamental canon of the scientific method is that observational results are to determine whether a theory is sound or not; whereas according to Hawking’s concept the theory (history of the universe) is adapted to the results of observation. “That, after all, denies us the chance to see if the theory matches up with observations.”
³

We have already said a lot about the multiverse in the previous chapters, and in this chapter, which is on metaphysical speculations concerning the anthropic principles, we cannot avoid the subject, either. All the more as an exceptional number of exceptionally fantastic ideas have sprung up around the notion of the multiverse. We shall take stock of some of them – not because they deserve special attention, but because they offer a good opportunity for a review of some of the philosophical aspects of the issue, which many authors treat rather perfunctorily.

Tegmark’s argument is simple and seems convincing. If the space of our universe extends out to infinity, which astronomical observations do not rule out, then any arbitrary configuration of atoms, even the least probable one, occurs an arbitrary number of times in it.
⁶
As he writes, “everything that could in principle have happened here did in fact happen somewhere else.”
⁷

We must admit that science, and especially modern physics, has often taught us a lesson about trusting too much to what is regarded as common sense, but it has also schooled us in sound criticism, indispensable especially when we are dealing with a concept as “wild” as infinity. In such situations it is good to consult the lesson of history. For a long time philosophers have been discussing the problem of the principle of individuation – the philosophical version of the question which sometimes even small children ask themselves: “Why am I?” An individual, especially a person with his/her own awareness, is more than just an ordinary aggregate of particles. What is it that makes something a particular, specific individual? And if a “principle of individuation” exists, does it not preclude the individual’s blueprinting in many copies? The fact that even in mathematics we come across a certain “principle of individuation” suggests we should take such a possibility into account. As we all know, the set of real numbers comprises an uncountable number of elements. But in spite of this every real number occurs just once in that endless set. No number comes a second time. What’s more, we are able to attribute a name to every real number (to any degree of accuracy), e.g. 0.123345…, and we can do this because each of them has its own individuality. What gives it an individuality is that every real number has properties which are proper only to itself (e.g. every real number has its own prime factorisation), and properties resulting from the order on the real number axis. This is a highly relevant example which should teach us to be extremely wary in embarking on intuitive speculations on the subject of infinity.

Many authors have certainly received the idea of the multiverse as an alternative to the concept of a Divine Designer: one had either to accept the existence of a Rational Creator, Who had so ordered the universe that we might come into existence within it; or acknowledge that there exists a vast (perhaps infinite) set of “all possible” universes, and we live in this particular one, since we could not have come into existence in any other. The choice is to a large extent a question of one’s philosophical preferences. Martin Rees considers the multiverse idea more rational,
⁸
while John Leslie sees the God hypothesis as more economical.
⁹

The point is, however, that it is not an exclusive, “either-or-but-not-both” alternative. The existence of even an infinite number of universes does not rule out the existence of God. As someone has pertinently observed, if God is infinite, then perhaps He is not interested in anything that is less than infinity. Theologians have for a very long time been speaking of the infinite fecundity of God in His activity of creation. Furthermore, the same questions pertain to an infinite number of universes as are asked with respect to just one universe: for instance, Leibniz’s question, “Why does something exist, rather than nothing?” (see Chap. 21). The philosophy of the multiverse does not remove the issue of God, but merely extends the range of the problem.

In the above reflections I have tacitly assumed the Christian concept of God (most of the thinkers I have discussed made the same assumption). But it is not a necessary assumption. In the history of human thought there have been many versions of Transcendence or the First Cause. Alongside the Theistic opinions, in which God is regarded as a Person, there have also been attitudes recognising an Ultimate Mind; a Deist, not necessarily personalised First Cause; and a Pantheist Substance. All these “keywords” are broad enough to include widely different opinions. The Ultimate Mind may assume a Christian version, not far from the ideas of St. Augustine and Leibniz. Deism has been associated with the idea of a Personal God Who created the world but entrusted its governance to the laws of nature, Himself as it were stepping aside; but Deism may also be viewed as connected with the existence of an impersonal Power permeating all the laws of nature. There is a continuum of such notions into Pantheism, which again may assume a variety of forms: from a simple identification of God with Nature, right up to the claim that the universe is the “body” of God. The notion of the universe existing within God, but God being transcendent with respect to the universe is referred to as Panentheism and is accommodated within Christian orthodoxy. We should also mention Emanationism, which over the centuries has proved a rather strong temptation for thinkers from the Christian milieu. The Church’s official pronouncements have often censured this tendency, which claims that the world came into existence not by being created, but by emanation, that is splitting off from the Divine Being. We could say that the contemporary pantheistic trends are an extension of the tendency to “divinise” the world.

The following criticism is often put, also in discussions on the multiverse, against the idea of God, whether personal or not. Whenever we ask for the cause of the existence of something, we are doomed to a chain of successive explanations: B is the cause of A, C is the cause of B … etc. Why should we have to stop the sequence of causal explanations at God; but if we ask for the cause of the existence of God we run the risk of
recursus ad infinitum
, an infinite sequence of successive questions.

I think this is an informative criticism. It errs by reducing God to the category of other,
finite
causes. But by very definition, God is the Necessary, Self-Existing Being. The reason for His existence is within Himself. Of course one may not accept the existence of such a Being, but if one acknowledges the existence of God, then that is what His Being is. The criticism is informative because it shows that only an infinite sequence of finite causes may replace the notion of God. There are good reasons for the claim made in the philosophy of God that He is the Infinite Being. The Infinite Cause is not the first link in the chain of causes. It justifies the existence of the entire chain, even if the chain were infinitely long.