Quotes from John D. Barrow

The first scientist to contemplate the significance of places where things apparently cease to exist or become infinite ('singularities' that we would Now call them) in Newtonian Theory where the 18th century scientist leonhard Euler and Roger boscovich.

There is, as we shall see, a real and precise difference between the number zero and the concept of a set that posesses no members - the null, or empty set. Indeed, the second idea, pointless as it sounds, turns out to be by far the most fruitful of the two. From it, all of the rest of mathematics can be created step by step.

The fact that simultaneous discovery occurs in mathematics, as well as the sciences, points toward some objective element within their subject matter that is independent of the psyche of the investigator.

The ease with which collaboration occurs in mathematical research and the essential similarity of the fruits of such collaboration to that of individual work points suggestively towards a powerful objective element behind the scenes that is discovered rather than invented.

Our brains are the most complicated objects that we have so far encountered in the Universe. We are far from simple. Indeed, were our brains significantly simpler, we would be too simple to know it.

We have seen that the process of stellar alchemy takes time – billions of years of it. And because our Universe is expanding it needs to be billions of light years in size if it is to have enough time to produce the building blocks for living complexity. A universe that was only as big as our Milky Way galaxy, with its 100 billion stars, would be little more than a month old.

Another consequence of an old expanding universe, besides its large size, is that it is cold, dark and lonely. When any ball of gas or radiation is expanded in volume, the temperature of its constituents falls off in proportion to the increase in its size. A universe that is big and old enough to contain the building blocks of complexity will be very cold and the levels of average radiant energy so low that space will everywhere appear dark.

If we were to smooth out all the material in the Universe into a uniform sea of atoms we would see just how little of anything there is. There would be little more than about 1 atom in every cubic metre of space. No laboratory on Earth could produce an artificial vacuum that was anywhere near as empty as that. The best vacuum achievable today contains approximately 1000 billion atoms in a cubic metre.

Life as we know, and partially understand it, is a classical example of what can occur when a sufficient level of complexity is attained. Consciousness appears to be a manifestation of an even more elaborate level of organization.

Science is predicated upon the belief that the Universe is algorithmically compressible and the modern search for a Theory of Everything is the ultimate expression of that belief, a belief that there is an abbreviated representation of the logic behind the Universe's properties that can be written down in finite form by human beings.

Typical stars, like our Sun, emit a wind of electrically-charged particles from their surface which will strip off the atmospheres of orbiting planets unless the wind can be deflected by a planetary magnetic field. In our solar system the Earth's magnetic field has protected its atmosphere from the solar wind but Mars, unprotected by any magnetic field, lost its atmosphere long ago.

Most scientists and mathematicians operate as if Platonism is true regardless of whether they believe that it is. That is, they work as though there were an unknown realm of truth to be discovered.

Particle physicists are the most deeply Platonic because their entire subject is built upon a belief that the deepest workings of the world are based upon symmetries. They examine symmetry after symmetry, confident in the expectation that the biggest and the best will have found employ in the grand scheme of things.

It is the cosmological vacuum energy that contributes a repulsive lambda force to the gravitational force of Newton.

Humans are distinguished further by the highly effective way in which they have pooled the individual intelligence of single individuals to produce a collective intelligence that greatly outweighs the capability of any single individual.

Today, a science fiction writer looking for a futuristic tale of silicon dominance would not pick upon the chemistry of silicon so much as the physics of silicon for his prognostications. But this form of silicon life could not have evolved spontaneously : it requires a carbon-based life-form to act as a catalyst. We are that catalyst.

For many years it had been claimed that the average achievement by pupils in some South-East Asian countries was significantly higher than in the United Kingdom. Then it came to light that the weakest pupils in that country were removed from the total who were evaluated at an earlier stage in the educational process. Clearly, the effect of their removal is to skew the average attainments to be higher than they would otherwise be.

All we can assert with confidence is a negative: if the constants of Nature were not within one percent or so of their observed values, then the basic buildong blocks of life would not exist in sufficient profusion in the Universe. Moreover, changes like this would affect the very stability of the elements and prevent the existence of the required elements rather than merely suppress their abundance.

The effect of the 'time becomes space' proposal is that there is no definite moment or point of creation. In more conventional quantum mechanical terms we would say that the universe is the result of a quantum mechanical tunneling process, where it must be interpreted as having tunneled from nothing at all. Quantum tunneling processes, which are familiar to physicists and routinely observed, correspond to Transitions which do not have a classical path.

there could be more than three dimensions of space but they had to be small and unchanging if they were to avoid altering the character of the world that we experience.

The pulsar is like a lighthouse beam spinning at high speed. Every time it comes around to face us we see a flash. Its rotation can be very accurately monitored by timing observations of its periodic pulses. Twenty years of observations have shown that the pulsing of the binary pulsar is slowing at exactly the rate predicted if the system is losing energy by radiating gravitational waves at the rate predicted by Einstein's theory.

Any string of symbols that can be given an abbreviated representation is called algorithmically compressible.

We can easily imagine worlds in which the constants of Nature take on slightly different numerical values where living beings like ourselves would not be possible. Make the fine structure constant bigger and there can be no atoms, make the strength of gravity greater and stars exhaust their fuel very quickly, reduce the strength of nuclear forces and there can be no biochemistry, and so on.

A condition, like the existence of stars or certain chemical elements, is identified as a necessary condition for the existence of any form of chemical complexity, of which life is the most impressive known example. This does not mean that if this condition is met that life must exist, will never die out if it does exist, or that the fact that this condition holds in our Universe means that it was 'designed' with life in mind.