Carl Sagan Quotes

After I give lectures-on almost any subject-I am often asked, "Do you believe in UFOs?" I'm always struck by how the question is phrased, the suggestion that this is a matter of belief and not evidence. I'm almost never asked, "How good is the evidence that UFOs are alien spaceships?"

Extraordinary observations require extraordinary evidence.

There is a lot of pseudo-science and nonsense out there on the Internet, and everyone feels the need to send it to me. And I'm sitting there thinking, 'It isn't real! Stop it!'

One problem with the focus on speculation is that it tends to promote the growth of the great intellectual cancer of our times: conspiracy theories.

There's no reason to be agnostic about ideas that are dramatically incompatible with everything we know about modern science.

Extraordinary claims require extraordinary evidence, and it is my job, my responsibility, as an astronomer to remind people that alien hypotheses should always be a last resort.

Without evidence, anything goes. Think about it. Common sense says the sun goes round the Earth. Who agrees with me?

There can be a conspiracy, but the presence of a conspiracy is actually not an excuse for conspiracy thinking.

I like the scientific spirit-the holding off, the being sure but not too sure, the willingness to surrender ideas when the evidence is against them: this is ultimately fine-it always keeps the way beyond open.

I am discounting the reports of UFOs. Why would they appear only to cranks and weirdos?

Science fiction is the most important literature in the history of the world, because it's the history of ideas, the history of our civilization birthing itself. ...Science fiction is central to everything we've ever done, and people who make fun of science fiction writers don't know what they're talking about.

There is no need to search for global solutions, apart from an absolute necessity to destroy the idea that such things exist.

On these matters of specific fact, like is the mushroom an extraterrestrial and that sort of thing, I haven't the faintest idea. The mushroom itself is such a mercurial, elusive, Zen sort of personality that I never believe a word it says. I simply entertain its notions and try and sort through them, and I found that to be the most enriching approach to it.

[E]xceptional claims demand exceptional evidence.

I think the greatest tragedy of mankind is that people have ideas and opinions in their heads but don't have a process for properly examining these ideas to find out what's true. That creates a world of distortions.

For years I've been stressing with regard to UFOs that extraordinary claims require extraordinary evidence.

In my view, the argument from parsimony is really no argument at all - it typically functions only to shut down more interesting discussion. If history is any guide, it's never a good idea to assume that a scientific problem is cornered.

Science is not sacrosanct. The mere fact that it exists, is admired, has results is not sufficient for making it a measure of excellence. Modern science arose from global objections against earlier views and rationalism itself, the idea that there are general rules and standards for conducting our affairs, affairs of knowledge included, arose from global objections to common sense.

I don't like people that make their living talking about bullshit, and you see them in many shows that are made on the same subject. When you go looking at UFOs or bigfoot or what-have-you, there's just nothing there.

The time must come inevitably when mankind shall surmount the imbecility of religion, as it has surmounted the imbecility of religion's ally, magic. It is impossible to imagine this world being really civilized so long as so much nonsense survives. In even its highest forms religion embraces concepts that run counter to all common sense. It can be defended only by making assumptions and adopting rules of logic that are never heard of in any other field of human thinking.

I do my precalc homework, and then when I'm done I actually sit with the textbook for like three hours and try to understand what I just did. That's the kind of weekend it is--the kind where you have so much time you go past the answers and start looking into the ideas.

With science, ideas can germinate within a bed of theory, form, and practice that assists their growth... But we as gardeners, must beware... for some seeds are the seeds of ruin... and the most iridescent blooms are often the most dangerous

No speech is ever considered, but only the speaker. It's so much easier to pass judgement on a man than on an idea.

If your mind is open to opposing ideas, your intelligence will go up. If your mind is closed to opposing ideas, your ignorance is in control. Intelligence or ignorance? Your ability to keep an open mind and appreciate multiple points of view is conscious choice. And one that can open your world, and shape your childs future.

I think that plain old intellectualism [can be] a more powerful force than the idea of the femme fatale.