Quotes from Stephen Hawking

as we all know, decisions are often not rational or are based on a defective analysis of the consequences of the choice. That is why the world is in such a mess.

if you feel you are in a black hole, don't give up: there is a way out!

Given the state of a system at some time, the laws of nature determine the probabilities of various futures and pasts rather than determining the future and past with certainty.

What most of these authors don't seem to have realized is that if you can travel faster than light, the theory of relativity implies you can also travel back in time, as the following limerick says: There was a young lady of Wight Who travelled much faster than light. She departed one day, In a relative way, And arrived on the previous night.

Since we know the universe itself was once very small—perhaps smaller than a proton—this means something quite remarkable. It means the universe itself, in all its mind-boggling vastness and complexity, could simply have popped into existence without violating the known laws of nature. From that moment on, vast amounts of energy were released as space itself expanded—a place to store all the negative energy needed to balance the books.

In space, no one can hear you scream; and in a black hole, no one can see you disappear.

So some might imagine that I am an expert on time, although of course these days an expert is not necessarily a good thing to be.

Visible light has a wavelength of between only forty and eighty millionths of a centimeter. Even shorter wavelengths are known as ultraviolet, X rays, and gamma rays. Maxwell's theory predicted that radio or light waves should travel at a certain fixed speed.

We also have some evidence that there is a much larger black hole, with a mass of about a hundred thousand times that of the sun, at the center of our galaxy.

Therefore, a human is equivalent to about fifty Harry Potter books, and a major national library can contain about five million books – or about ten trillion bits.

a scientific theory is just a mathematical model we make to describe our observations: it exists only in our minds. So it is meaningless to ask: which is real, real or imaginary time? It is simply a matter of which is the more useful description.

In effect, God was confined to the areas that nineteenth-century science did not understand.

As the poet Alexander Pope said: Nature and Nature's laws lay hid in night: God said, Let Newton be! and all was light.

I think it is legitimate to take a broader view and include externally transmitted information, as well as DNA, in the evolution of the human race.

I have no idea. People who boast about their I.Q. are losers.

In 1992 the Roman Catholic Church finally acknowledged that it had been wrong to condemn Galileo.

The Catholic Church, on the other hand, seized on the big bang model and in 1951 officially pronounced it to be in accordance with the Bible.) There

The eventual goal of science is to provide a single theory that describes the whole universe

to explain how the early universe

However bad life may seem, where there is life, there is hope.

By contrast, there are about 50,000 new books published in the English language each year, containing of the order of a hundred billion bits of information. Of course, the great majority of this information is garbage and no use to any form of life. But, even so, the rate at which useful information can be added is millions, if not billions, higher than with DNA.

Sin embargo, si descubrimos una teoría completa, debería en su momento ser comprensible en sus líneas generales por todos, no solo por unos pocos científicos. Entonces todos seremos capaces de tomar parte en la discusión de por qué el universo existe. Si encontramos la respuesta a ello, sería el triunfo definitivo de la razón humana, pues entonces conoceríamos la mente de Dios.

Humanity's deepest desire for knowledge is justification enough for our continuing quest.

These laws may have originally been decreed by God, but it appears that he has since left the universe to evolve according to them and does not now intervene in it.