Islam and Science: concordance or Conflict? By Prof. Abdus Salam 4/5

The Limitations of Science

In his remarks, the Pope stressed the maturity which the Church had reached in dealing with science; he could equally have emphasised the converse—the recognition by the scientists from Galileo’s times onwards, of the limitations of their disciplines—the recognition that there are questions which are beyond the ken of present or even future sciences. We may speculate about some of them, but there may be no way to verify empirically our speculations. And it is this empirical verification that is the essence of modern science. We are humbler today than, for example, Ibn Rushd (Averroes) was. Ibn Rushd was a physician of great originality with major contributions in the study of fevers and of the retina; this is one of his claims to scientific immortality. However, in a different discipline—cosmology—he accepted the speculations of Aristotle, without recognising that these were speculations, and that future experiments may prove them false. The scientist of today knows when and where he is speculating; he would claim no finality for the associated modes of thought. And even about accepted facts, we recognise that newer facts may be discovered which, without falsifying the earlier discoveries, may lead to generalisations; in turn, necessitating revolutionary changes in our concepts and our “world-view.” In physics, this happened in the beginning of this century with the discovery of relativity and quantum theory. It could happen again; with our present constructs appearing as limiting cases of the newer concepts, still more comprehensive, still more embracing.

I have been asked to elaborate on this.

I have mentioned the revolution in the physicists’ concepts of the relativity of time. It appears incredible that the length of a time interval depends on one’s speed— that the faster we move the longer we appear to live to someone who is not moving with us. And this is not a figment of one’s fancy. Come to the particle physics laboratories of CERN at Geneva which produce short-lived particles like muons, or the laboratories here at Orsay, and make a record of the intervals of time which elapse before muons of different speeds decay into electrons and neutrinos. The faster muons take longer to die, the slower ones die early, precisely in accord with the quantitative law of relativity of time first enunciated by Einstein in 1905. It took time for physics to verify and comprehend Einstein. Fortunately, it seems no philosopher has understood Einstein. To my knowledge, no system of philosophy appears to have been erected on his ideas of space and time.

The second and potentially the more explosive revolution in thought came in 1926 with Heisenberg’s Uncertainty Principle. This principle concerns the existence of a conceptual limitation on our knowledge. It affirms, for example, that no physical measurements can tell you that there is an electron on this table and also that it is lying still. Experiments can be made to discover where the electron is; these experiments will then destroy any possibility of finding simultaneously whether the electron is moving and if so at what speed. There is an inherent limitation on our knowledge, which appears to have been decreed. I shudder to think what might have happened to Heisenberg if he was born in the Middle Ages—just what theological battles might have raged on whether there was a like limitation on the knowledge possessed by God.

As it was, battles were fought, but within the 20th century physics community. Heisenberg’s revolutionary thinking, supported by all known experiment, has never been accepted by all physicists. The most illustrious physicist of all times, Einstein, spent the best part of his life trying to find flaws in Heisenberg’s arguments. He could not gainsay the experimental evidence, but he hoped that such evidence may perhaps be explained within a different theoretical framework. Such framework has not been found so far, notwithstanding Einstein’s repeated attempts. It appears unlikely, but who among us can assert that it may never be discovered.

Is the science of today on a collision course with metaphysical thinking? Let us consider some examples of modern scientific thinking in this context.

My first example concerns the metaphysical doctrine of the creation from nothing. Today we believe in cosmology, that the most likely value for the density of matter and energy in the universe is such that the mass of the universe adds up to zero, precisely. The mass of the universe is defined as the sum of the masses and energies of the electrons, the protons, photons and neutrinos, which constitute the universe minus an expression for their mutual gravitational energies. If the mass of the universe is indeed zero, and this is an empirically determinable quantity—the universe shares with the vacuum state the property of masslessness. A bold extrapolation made as recently as a decade back then treats the universe as a quantum fluctuation of the vacuum—of the state of nothingness. I must emphasise here that what distinguishes physics from metaphysics is that this bold extrapolation can and will be tested by measuring the density of matter in the universe more and more precisely. We shall know empirically whether the idea can be sustained in the physicists’ sense. If it cannot be, we shall discard it.

My second example is the principle of the anthropic universe—the assertion by a number of cosmologists that one way to understand the processes of cosmology, geology, biochemistry and biology is to assume that our universe was conceived in a potential condition and with physical laws, which possess all the necessary ingredients for the emergence of life and intelligent beings. “Basically this potentiality relies on a complex relationship between the expansion and the cooling of the universe, after the Big Bang, on the behaviour of the free energy of matter, on the intervention of chance at various levels,” as well as on a number of coincidences which we shall have to explain and which have permitted the universe to survive a few billion years.

Consider some of the elements of this story as told by Carr, Rees and Hubert Reeves.9 The universe started with a Big Bang; as it expanded and thereby cooled, quarks bound themselves through the well-known physical forces into nucleons, these with electrons into atoms, and the atoms into galaxies and stars.

“It is of interest to note that stars can form only if they can emit light and heat and emission of light and heat can take place only in a cold universe. This is guaranteed by the expansion itself. If the universe was to stop expanding, all structure—including living structures—would be dismantled. If the night were not dark, there would be no one to notice it.”

Now, normally, nuclear binding should proceed by reaching for the lowest possible stable state. “Nuclear binding, on a cosmic scale, however, stops short of reaching this lowest state. In principle, Big Bang nucleosynthesis could have yielded a world of iron. In fact we hardly go past helium in the table of nuclei. Why? Because the number of relativistic particles per unit volume created was not high enough.” Equilibrium ceased before nuclear evolution reached its lowest state. Did this happen because iron is hardly an appropriate element to promote life?

“Next we come to a second chapter of organization of matter. The first chapter, from the Big Bang to the birth of the first stars is a chapter of global organization following the decline of cosmic temperature. The second chapter witnesses the rise of complexity in a local scale around the multitude of stars, with their hot interiors and warm surroundings.”

The stars formed according to standard cosmological laws: they exploded whenever they were larger than a certain size. This time however heavy nuclei were formed—generating ices NH3, CH4, H20, complex molecules, and grains of dust of iron-magnesium silicate. And around a later generation of stars these grains and ices gave birth to planets with atmospheres and oceans into which chemical evolution pursued its course.

“Is the future of the universe and in particular the course of events leading to this organization, implicitly written down in the laws of physics from the very beginning?” It appears NOT. The chemist and the biologist tell us that the “physical processes have not always been in equilibrium. We have a large number of energetically equivalent states, and it is between these states that the game of organization takes place, largely through the effect of chance”—chance, presumably guided and driven by the biologists’ principle of “need for survival.”

I am longing at this point for my biological colleagues to take up the story and tell us of the operation of their non-equilibrium and the principle of survival mechanism. The equilibrium physicist has, however, a principle analogous to this. We call it the principle of self-consistency. Since I am more familiar with it, I shall illustrate its operation, so far as the coincidences I referred to earlier are concerned, by taking an example of something I am currently working on myself.

As an extension of the recent excitement in physics—that is of our success in unifying and establishing the identity of two of the fundamental forces of nature, the electric and the weak nuclear—we are now considering the possibility that space-time may have 11 dimensions. Within this context we hope to unify the electroweak force with the remaining two basic forces, gravity and the strong nuclear. Of the 11 dimensions which we have postulated, four are the familiar dimensions of space and time. The other seven dimensions are supposed to correspond to a hidden internal manifold—hidden because these seven dimensions are assumed to have curled in upon themselves to fantastically tiny dimensions of the order of 10-33cms. We live on the surface of a cylinder in the 11-dimensional space: our major source of sensory apprehension of these extra dimensions being the existence of familiar charges—electric and nuclear—which in their turn produce the familiar electric and the nuclear forces.

Exciting idea, which may or may not work quantitatively. But one question already arises; why the difference between the four familiar space-time dimensions and the seven internal ones? And why 11 dimensions in the first place, and not a wholesome number like 13 or 19? Were these 11 dimensions on par at the beginning of time? Why have the seven curled in upon themselves, while the other four have not? At present, we make this plausible by postulating a self-consistency principle; we invent a field of force designed to guarantee this configuration as the only stable self-consistent dynamical system which can exist. But there will be a price to pay.

There will be a subtle physical consequence of this hypothesis, for example, in the form of remnants, like the three degree radiation which we believe was a remnant of the recombination era following on the Big Bang. We shall search for these remnants. If we do not find them, we shall abandon the idea.

Creation from nothing, an anthropic universe, extra dimensions—strange topics for late 20th century physics—which appear no different from metaphysical preoccupations of earlier times. But so far as science is concerned, mark the provisional nature of the conceptual edifice, the insistence on empirical verification at each stage and the concept of driving self-consistency.

For the agnostic, self-consistency (if successful) may connote irrevelance of a deity. For the believer, it provides no more than an unravelling of a small part of the Lord’s design—its profundity, in the areas it illuminates, only enhances his reverence for the beauty of the design itself.

I can offer no new resolution, except to make two remarks. First, I find the creationist creed insulting that while we are willing to ascribe subtlety to ourselves in devising these self-consistency modalities, the only subtlety we are willing to ascribe to the Lord is that of the potter’s art—kneading clay and fashioning it into man. I do not see why once having created certain attributes within matter, and the laws which govern the operation of the fundamental forces, the path we follow in physics is not creationism in the wider sense.

My second remark is personal. Personally for me, my faith was predicted by the timeless spiritual message of Islam, on matters on which physics is silent. It was given meaning to by the very first verse of the Holy Qur’an after the opening:

“This is the Book, wherein there is no doubt, a guidance to the God-fearing, who believe in the unseen.”10

The unseen—beyond the reach of human ken—the unknowable.

By Professor Abdus Salam, to be continued…


9.  H. Reeves, The Birth of the Universe, (Paris: Frontieres, 1982) 369.

10.  Holy Qur’an, Surah Al-Baqarah, Verses 3-4. The English translation by Maulawi Sher Ali for these verses reads as follows: “This is a perfect Book; there is no doubt in it; it is a guidance for the righteous, Who believe in the unseen and observe Prayer, and spend out of what We have provided for them.”