In January 1939, the physicist Luis Alvarez was sitting in a barber's chair in Berkeley, California, reading the paper and getting a haircut. It was then that he read something astonishing; scientists in Germany had bombarded uranium with neutrons and had actually observed it splitting into two light elements, releasing further neutrons and a disturbingly intense pulse of energy. It was exactly the kind of experiment that Alvarez and his student Philip Abelson had been trying to do. Unconcerned about his incomplete haircut, Alvarez leapt from his chair and went to see the reigning American theoretical physicist of his time, Robert Oppenheimer. Upon hearing what had happened, Oppenheimer quickly gave Alvarez a complicated theoretical explanation for why fission could never occur. Exasperated, Alvarez led Oppenheimer to his laboratory where he and Abelson had rigged up their own experiment. With a little manipulation he could show Oppenheimer the ionization spikes that fission fragments produce on an oscilloscope. Theory trumped by hard experiment, Oppenheimer quickly realized that fission was real.

Those ionization pulses that Oppenheimer and Alvarez saw that day were the "truth". The fact that uranium fissions when bombarded by neutrons is the "truth". The atomic nucleus is "real".

Why am I narrating the story of the reality of fission? Because there are still those who want to disown science because, in their apparently considered opinion, all science can do is to produce doubt. One of those who get the essence of science wrong is Yahoo columnist Virginia Heffernan. Much has been written about her piece on Yahoo in which she declares herself to be a creationist, and I cannot add to the existing excellent takedowns by people who wasted their precious time trying to bridge the intellectual chasm in Heffernan's head. Her column is uninspired, intellectually lazy, rambling and does not even make a pretense at addressing what science actually is. It sounds like it was written by someone who suddenly found 30 minutes on their Friday evening calendar cleared up and wanted to make a quick, uninformed and unlettered surgical strike at those awful scientists just before they left to join their friends for dinner and a movie. The column is so lazily written that even creationists should feel embarrassed.

In any case, almost nothing in the piece sounds like the author actually thought about it, but there was one aspect of the rant that deserves a little more attention, if only because it seems to have received less attention from Heffernan's critics. One of Heffernan's gripes about scientists is that they are "super-skeptical" types who cannot seem to agree on anything. She selectively points to fields like evolutionary psychology - a field that is still in its infancy and which is seeing its wheat separated from the chaff in a customary process of brutal trial-by-fire - as an example of science's ever-changing and never-certain landscape. She thinks that compared to scientists who just can't seem to decide, religion at least offers some answers.

Now let's discount for a moment that the "answers" that religion offers are completely subjective - what a Christian believes is dismissed as fiction by a Buddhist - but Heffernan's take on scientific doubt is at best woefully incomplete and in reality just plain wrong. Let's understand one thing loud and clear; science is concerned with the truth. It really is.

Those who refuted Heffernan affirmed her words about doubt and skepticism and held them up as glowing tributes to science. There is no doubt that skepticism is at the heart of scientific inquiry, that any scientist worth his or her salt should live and die by the Royal Society's motto "Nullius in Verba", or "Nobody's word is final". All of us are fond of quoting Richard Feynman: "I think it's much more interesting to live not knowing than to have answers which might be wrong". Heffernan's critics are absolutely right that the doubt which she abhors is the oxygen which science thrives on, but it's really important to understand that there is in reality a shining galaxy of truths uncovered by science, truths whose veracity has been established beyond any reasonable doubt. While it is indeed endlessly interesting to live not knowing, there is actually a hell of a lot of stuff that we know, and that we know is true.

The fact that DNA is a double helix is a truth. The fact that organisms evolve through natural selection is a truth. The fact that a massive body causes spacetime to bend around it is a truth. There are other timeless truths; the atomic nucleus is made up of protons and neutrons, the earth goes around the sun, water consists of two hydrogen atoms and an oxygen, mercury become superconducting below a certain temperature, gravity obeys an inverse square law, the universe is expanding, energy can neither be created nor destroyed. Every single one of these facts is a truth which is known with enough certainty to be carved in stone. These truths not only provide science with a concrete direction for progress, but they provide solace in the world of politics and human affairs which is actually uncertain; it is no surprise that scientists growing up in fascist regimes, like the ones thriving in the 1920s, turned toward science precisely because it offered the kind of certainty that the volatile world around them did not.

Now of course the scientific method demands that in principle every one of the above truths be provisional, that every one of them should continue to be subjected to the most unsparing scrutiny, subject to change in the face of definitive evidence to the contrary. And science makes no claim to addressing every single issue confronting humanity, such as questions of morality. But no scientist believes that any of the above hallowed facts that science has discovered will be proven fundamentally wrong. The real beauty of it all though is that we arrived at all these truths through the vehicle of doubt. No other system of human inquiry goes about discovering truth through the medium of doubt the way science does.

It would of course be right up the alley of creationists like Heffernan to belabor that old chestnut; that because there is debate about the details or subtleties of a theory or scientific framework, that must mean that the entire edifice is crumbling. It's a stale old tactic and there's absolutely nothing new about it. Are scientists still having debates about the rate of evolution? Do they still argue about the relative importance of natural selection vs random genetic drift? That must mean all of evolution must be wrong. Whatever political agenda creationists are serving by touting these falsehoods, their words always demonstrate a fundamental ignorance of science and an even greater ignorance of the bare facts about the universe that science has discovered.

So no, Virginia Heffernan and other creationists, you are wrong that all that science offers is doubt. Doubt is only a medium - and a spectacularly successful one at that - to get to the truth. Unlike religion whose truths differ for every person, science actually offers universal truths that can be tested, repeated and verified by anyone who cares to do so. I would rather live exploring the hard road to these timeless truths which are all too real rather than bask in the false glow of ones whose reality can never be demonstrated.