اقوال جميلة ل كارل ساغان
The secrets of evolution are death and time—the deaths of enormous numbers of lifeforms that were imperfectly adapted to the environment; and time for a long succession of small mutations.

While our behavior is still significantly controlled by our genetic inheritance, we have, through our brains, a much richer opportunity to blaze new behavioral and cultural pathways on short timescales.

A universe in which everything is known would be static and dull, as boring as the heaven of some weak-minded theologians...The ideal universe for us is one very much like the universe we inhabit...not really much of a coincidence.

Advances in medicine and agriculture have saved vastly more lives than have been lost in all wars in history.

Can we know, ultimately and in detail, a grain of salt?...In that grain of salt there are about...10 million billion atoms...Now, is this number more or less than the number of things which the brain can know?

Chlorine is a deadly poison gas employed on European battlefields in World War I. Sodium is a corrosive metal which burns upon contact with water. Together they make a placid and unpoisonous material, table salt. Why each of these substances has the properties it does is...chemistry.

Instead of acknowledging that in many areas we are ignorant, we have tended to say things like the Universe is permeated with the ineffable. A God of the Gaps is assigned responsibility for what we do not understand.

It is an astonishing fact that there are laws of nature, rules that summarize conveniently—not just qualitatively but quantitatively—how the world works

Occasionally someone remarks on what a lucky coincidence it is that the Earth is perfectly suitable for life...But this is, at least in part, a confusion of cause and effect.

Pseudoscience is easier to contrive than science...The standards of argument, what passes for evidence, are much more relaxed. In part for these reasons, it is much easier to present pseudoscience to the general public than science.

Pseudoscience is embraced, it might be argued, in exact proportion as real science is misunderstood.

Science is far from a perfect instrument of knowledge. It's just the best we have.

The consequences of scientific illiteracy are far more dangerous in our time than in any that has come before.

The reason science works so well is partly that built-in error-correcting machinery. There are no forbidden questions in science, no matters too sensitive or delicate to be probed, no sacred truths.

We are not in the habit of traveling close to the speed of light. The testimony of our common sense is suspect at high velocities.

We can pray over the cholera victim, or we can give her 500 milligrams of tetracycline every 12 hours.

A galaxy is composed of gas and dust and stars—billions upon billions of stars.

Our loyalties are to the species and the planet. We speak for Earth. Our obligation to survive is owed not just to ourselves but also to that cosmos, ancient and vast, from which we spring.

To make an apple pie from scratch, you must first invent the universe.