Teller contended, not implausibly, that hydrogen bombs keep the peace, or at least prevent thermonuclear war, because the consequences of warfare between nuclear powers are now too dangerous. We haven't had a nuclear war yet, have we? But all such arguments assume that the nuclear-armed nations are and always will be, without exception, rational actors, and that bouts of anger and revenge and madness will never overtake their leaders (or military and secret police officers in charge of nuclear weapons). In the century of Hitler and Stalin, this seems ingenuous.
The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.
'In his celebrated book, 'On Liberty', the English philosopher John Stuart Mill argued that silencing an opinion is "a peculiar evil." If the opinion is right, we are robbed of the "opportunity of exchanging error for truth"; and if it's wrong, we are deprived of a deeper understanding of the truth in its "collision with error." If we know only our own side of the argument, we hardly know even that: it becomes stale, soon learned by rote, untested, a pallid and lifeless truth.'
Eratosthenes's only tools were sticks, eyes, feet, and brains; plus a zest for experiment. With those tools he correctly deduced the circumference of the Earth, to high precision, with an error of only a few percent. That's pretty good figuring for 2200 years ago.
Goddard represented a unique combination of visionary dedication and technological brilliance. He studied physics because he needed physics to get to Mars. In reading the notebooks of Robert Goddard, I am struck by how powerful his exploratory and scientific motivations were - and how influental speculative ideas, even erroneous ones, can be on the shaping of the future.
Who are we? We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people.
These are all cases of proved or presumptive baloney. A deception arises, sometimes innocently but collaboratively, sometimes with cynical premeditation. Usually the victim is caught up in a powerful emotion -- wonder, fear, greed, grief. Credulous acceptance of baloney can cost you money; that's what P. T. Barnum meant when he said, 'There's a sucker born every minute.' But it can be much more dangerous than that, and when governments and societies lose the capacity for critical thinking, the results can be catastrophic -- however sympathetic we may be to those who have bought the baloney.
If we are merely matter intricately assembled, is this really demeaning? If there's nothing here but atoms, does that make us less or does that make matter more?
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.
Science is based on experiment, on a willingness to challenge old dogma, on an openness to see the universe as it really is. Accordingly, science sometimes requires courage - at the very least the courage to question the conventional wisdom.
The method of science is tried and true. It is not perfect, it's just the best we have. And to abandon it, with its skeptical protocols, is the pathway to a dark age.
We have begun to contemplate our origins: starstuff pondering the stars; organized assemblages of ten billion billion billion atoms considering the evolution of atoms; tracing the long journey by which, here at least, consciousness arose.
All of the rocky and metallic material we stand on, the iron in our blood, the calcium in our teeth, the carbon in our genes were produced billions of years ago in the interior of a red giant star. We are made of star stuff.
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.