My satire about “alternative facts” from yesterday took some flak for propagating the controversial photos of inaugurations that some say are real and some say aren’t. I don’t honestly care one bit about those photos. I think it is of absolutely no importance how many people went to Trump’s inauguration; it has no bearing on how he will perform as president, and frankly I don’t know why he’s making such a big deal out of it. Even if attendance was far less than he and his people claim, it could be for two very good reasons that would not reflect badly on him at all.

First, Obama’s inauguration was extraordinarily historic. For a nation with our horrific past —  with most of our dark-skinned citizens brought to this continent to serve as property and suffer under slavery for generations — it was a huge step to finally elect an African-American president. I am sure many people chose to go to the 2009 inauguration because it was special to them to be able to witness it, and to be able to say that they were there. Much as many people adore Trump, it’s not so historic to have an aging rich white guy as president.

Second, look at a map of the US, with its population distribution. A huge population with a substantial number of Obama’s supporters live within driving distance or train distance of Washington DC. From South Carolina to Massachusetts there are large left-leaning populations. Trump’s support was largest in the center of the US, but people would not have been able to drive from there or take a train. The cost of travel to Washington could have reduced Trump’s inauguration numbers without reflecting on his popularity.

So as far as I’m concerned, it really doesn’t make any difference if Trump’s inauguration numbers were small, medium or large. It doesn’t count in making legislation or in trade negotiations; it doesn’t count in anything except pride.

But what does count, especially in foreign affairs, is whether people listen to what a president says, and by extension to what his or her press secretary says. What bothers me is not the political spinning of facts. All politicians do that. What bothers me is the claim of having hosted “the best-attended inauguration ever” without showing any convincing evidence, and the defense of those claims (and we heard it again today) that this is because it’s ok to disagree with facts.

If facts can be chosen at will, even in principle, then science ceases to function. Science — a word that means “evidence-based reasoning applied logically to determine how reality really works” — depends on the existence and undeniability of evidence. It’s not an accident that physics, unlike some subjects, does not have a Republican branch and a Democratic branch; it doesn’t have a Muslim, Christian, Buddhist or Jewish branch;  there’s just one type.  I work with people from many countries and with many religious and political beliefs; we work together just fine, and we don’t have discussions about “alternative facts.”

If instead you give up evidence-based reasoning, then soon you have politics instead of science determining your decisions on all sorts of things that matter to people because it can hurt or kill them: food safety, road safety, airplane safety, medicine, energy policy, environmental protection, and most importantly, defense. A nation that abandons evidence is abandoning applied reason and logic; and the inevitable consequence is that people will die unnecessarily.  It’s not a minor matter, and it’s not outside the purview of scientists to take a stand on the issue.

Meanwhile, I find the context for this discussion almost as astonishing as the discussion itself. It’s one thing to say unbelievable things during a campaign, but it’s much worse once in power. For the press secretary on day two of a new administration to make an astonishing and striking claim, but provide unconvincing evidence, has the effect of completely undermining his function.  As every scientist knows by heart, extraordinary claims require extraordinary evidence.  Imagine the press office at the CERN laboratory announcing the discovery of the Higgs particle without presenting plots of its two experiments’ data; or imagine if the LIGO experimenters had claimed discovery of gravitational waves but shown no evidence.  Mistakes are going to happen, but they have to be owned: imagine if OPERA’s tentative suggestion of neutrinos-faster-than-light, which was an experimental blunder, or BICEP’s loud misinterpretation of their cosmological data, had not been publicly retracted, with a clear public explanation of what happened.  When an organization makes a strong statement but won’t present clear evidence in favor, and isn’t willing to retract the statement when shown evidence against it, it not only introduces immediate suspicion of the particular claim but creates a wider credibility problem that is extremely difficult to fix.

Fortunately, the Higgs boson has been observed by two different experiments, in two different data-taking runs of both experiments; the evidence is extraordinary.  And LIGO’s gravitational waves data is public; you can check it yourself, and moreover there will be plenty of opportunities for further verification as Advanced VIRGO comes on-line this year.    But the inauguration claim hasn’t been presented with extraordinary evidence in its favor, and there’s significant contradictory evidence (from train ridership and from local sales).    When something extraordinary is actually true, it’s true from all points of view, not subject to “alternative facts”; and the person claiming it has the responsibility to find evidence, of several different types, as soon as possible.  If firm evidence is lacking, the claim should only be made tentatively.  (A single photo isn’t convincing, one way or the other, especially nowadays.)

As any child knows, it’s like crying wolf.  If your loud claim isn’t immediately backed up, or isn’t later retracted with a public admission of error, then the next time you claim something exceptional, people will just laugh and ignore you.  And nothing’s worse than suggesting that “I have my facts and you have yours;” that’s the worst possible argument, used only when firm evidence simply isn’t available.

I can’t understand why a press secretary would blow his credibility so quickly on something of so little importance.  But he did it.  If the new standards are this low, can one expect truth on anything that actually matters?  It’s certainly not good for Russia that few outside the country believe a word that Putin says; speaking for myself, I would never invest a dollar there. Unfortunately, leaders and peoples around the world, learning that the new U.S. administration has “alternative facts” at its disposal, may already have drawn the obvious conclusion.    [The extraordinary claim that “3-5 million” non-citizens (up from 2-3 million, the previous version of the claim) voted in the last election, also presented without extraordinary evidence, isn’t helping matters.] There’s now already a risk that only the president’s core supporters will believe what comes from this White House, even in a time of crisis or war.

Of course all governments lie sometimes.  But it’s wise to tell the truth most of the time, so that your occasional lies will sometimes be thought to be true.  Governments that lie constantly, even pointlessly, aren’t believed even when they say something true.  They’ve cried wolf too often.

So what’s next?  Made-up numbers for inflation, employment, the budget deficit, tax revenue? Invented statistics for the number of people who have health insurance?  False information about the readiness of our armed forces and the cost of our self-defense?  How far will this go?  And how will we know?