Quotes from John D. Barrow

The specific nuclear reaction that is needed to make carbon is a rather improbable one. It requires three nuclei of helium to come together to fuse into a single nucleus of carbon.

If the fine structure constant, that governs the strength of electromagnetic forces, were changed by more than 4 per cent or the strong force by more than 0.4 of one per cent then the production of carbon or oxygen would be reduced by factors of between 30 and 1000.

A change of more than 0.4 per cent in the constants governing the strength of the strong nuclear force or more than 4 per cent in the fine structure constant would destroy almost all carbon or almost all oxygen in every star.

by means of evolution by natural selection, which showed how living things can become well adapted to their environments over the course of time under a very wide range of circumstances, so long as the environment is not changing too quickly. Complexity could develop from simplicity without direct Divine intervention.

Anselm conceives of God as something than which nothing greater or more perfect can be conceived. Since this idea arises in our minds it certainly has an intellectual existence. But does it have an existence outside of our minds? Anselm argued that it must, for otherwise we fall into a contradiction. For we could imagine something greater than that which nothing greater can be conceived; that is the mental conception we have together, plus the added attribute of real existence.

Since so much of the physical universe, from brain waves to quantum waves, relies upon travelling waves we appreciate the key role played by the dimensionality of our space in rendering its contents intelligible to us.

As we look way back into the first instants of the Big Bang, we find the quantum world that we described in Chapter 3. From that state, where like effects do not follow from like causes, there must somehow emerge a world resembling our own, where the results of most observations are definite. This is by no means inevitable and may require the Universe to have emerged from a rather special primeval state.

Whatever the ultimate Theory of Everything is found to be, it will have a limiting form which describes motion at speeds far less than that of light in weak gravity fields where quantum wavelike features of mass are negligible. This form will be the one that Newton found.

Everything that is made of atoms has a density quite close to the density of a single atom given by the mass of an atom divided by its volume.

The quantum wavelength of a particle gets smaller the more massive the particle. Situations are dominated by quantum waviness when the quantum wavelength of their participants exceeds their physical size. Everyday objects, like cars and speeding cricket balls, have such high masses that their quantum wavelengths are vastly smaller than their sizes and we can forget about quantum influences when driving cars or watching cricket matches.

One of the curious problems of physics is that it has two beautifully effective theories – quantum mechanics and general relativity – but they govern different realms of Nature.

Quantum mechanics holds sway in the microworld of atoms and elementary particles. It teaches us that every mass in Nature, however solid or pointlike it may appear, has a wavelike aspect. This wave is not like a water wave. It is more analogous to a crime wave or a wave of hysteria: it is a wave of information.

Others might point to the warning that the most dangerous thing in science is the idea that arrives before its time.

Moreover it is assumed that wormholes only join universes to baby universes, or universes to themselves; there are no wormholes joining different baby universes in this approximation, nor are there allowed to be wormholes which split up into two or more other wormholes.

Once upon a time there was no Time.

There was no 'before' the beginning of our universe, because once upon a time there was no time.

There is no reason that the universe should be designed for our convenience.

History is full of people who thought they were right -- absolutely right, completely right, without a shadow of a doubt. And because history never seems like history when you are living through it, it is tempting for us to think the same.

Any universe simple enough to be understood is too simple to produce a mind able to understand it -Barrow's Uncertainty Principle

There are only certain intervals of time when life of any sort is possible in an expanding universe and we can practise astronomy only during that habitable time interval in cosmic history.

If the deep logic of what determines the value of the fine-structure constant also played a significant role in our understanding of all the physical processes in which the fine-structure constant enters, then we would be stymied. Fortunately, we do not need to know everything before we can know something.

Prior to then it was believed that black holes were just cosmic cookie monsters, swallowing everything that came within their gravitational clutches.

We can measure the fine structure constant with very great precision, but so far none of our theories has provided an explanation of its measured value. One of the aims of superstring theory is to predict this quantity precisely. Any theory that could do that would be taken very seriously indeed as a potential 'Theory of Everything'.

I love cosmology: there's something uplifting about viewing the entire universe as a single object with a certain shape. What entity, short of God, could be nobler or worthier of man's attention than the cosmos itself? Forget about interest rates, forget about war and murder, let's talk about space." Rudy Rucker21