Wednesday, April 27, 2016

Lunar Certainty

"All this talk about space travel is utter bilge, really. It would cost as much as a major war just to put a man on the moon." (Richard van der Riet Woolley, 1956)

When Apollo 11 splashed down in the Pacific Ocean on July 24, 1969, it fulfilled John F. Kennedy's promise, made in 1961, of landing a man on the surface of the moon and returning him safely to earth before the decade was over. This remains humanity's greatest feat of engineering. It is without doubt the longest voyage any human being has undertaken, and required an enormous coordination of resources to succeed. Even a conservative estimate puts the price of the Apollo program at over 20 billion 1973 dollars (over 100 billion today). "At its peak," says NASA, "the Apollo program employed 400,000 people and required the support of over 20,000 industrial firms and universities." By the end of 1972, NASA had landed twelve men on the surface of the moon. All returned safely.

How do I know this? Well, as I was writing the above paragraph I had the Wikipedia article on the Apollo program open in another window. The precise dates and figures are all taken from there. But does that mean that until today, when I was writing this post, I didn't know these things? Certainly, none of the facts I have just presented surprised me. I doubt they surprise very many of my readers. There's nothing new in these facts. We have known this for a long time.

Indeed, all of these facts have been present to me with as much or greater precision before. I've long been interested in the accomplishment of the Apollo program, mainly out of my disappointment that there are no cities on the moon today. Given that the American government spent more than five times as much prosecuting a war in Vietnam at about the same time, the argument that it was too expensive to continue to explore and colonize the moon seems somewhat disingenuous to me. That's just my opinion, of course. The facts I stated in the first paragraph are what they are independent of the reason they interest me.

I'm also interested in this fact because it is at once the most amazing and most ordinary fact of our culture. The Wikipedia article is almost certainly reliable on most details. Each fact can be checked independently in multiple sources as well. Everyone knows we have been to the moon. But only seven living human beings can know for certain. How I know that they have been to the moon is one thing; how they know is another. What is remarkable, what is actually somewhat amazing, is that we can know that these men have stood on the surface of our only natural satellite, 400,000 kilometers away.

What is also remarkable is that before 1969 we could be as certain that no human had ever been there. In On Certainty, for example, Wittgenstein returns again and again to the proposition, "I have never been on the moon." He takes this as an exmple of the sort of thing it is not possible to doubt. §286 is a good example:

What we believe depends on what we learn. We all believe that it isn't possible to get to the moon; but there might be people who believe that that is possible and that it sometimes happens. We say: these people do not know a lot that we know. And, let them be never so sure of their belief—they are wrong and we know it./ If we compare our system of knowledge with theirs then theirs is evidently the poorer one by far.

That was written in 1950. Suppose we said the following today:

What we believe depends on what we learn. We all believe that it is possible to get to the moon; but there might be people who believe that that it is not possible and that it never happened. We say: these people do not know a lot that we know. And, let them be never so sure of their belief—they are wrong and we know it./ If we compare our system of knowledge with theirs then theirs is evidently the poorer one by far.

In fact, there are people who believe that we have never been on the moon. These are the so-called "cranks" who think the Apollo program was a hoax. (Interestingly, even they will grant that I've provided a clear prose statement of the "official story" in my first paragraph.) As I see it, they hold two fundamental beliefs: (a) it was indeed impossible to get to the moon in 1950 and remained so for the next 20 years, (b) an "official" assurance that something has happened is no reason to believe that something has in fact happened. After that there are the details: the discussion of the "anomalies" that reveal that the evidence NASA provides is faked, and so forth.

In any case, since these people do not believe that anyone has been to them moon, they do not know that we have been there. They have a different "system of knowledge", we might say. It is marvelously different, indeed; and one may rightly wonder how they know anything at all.

More to come.

2 comments:

Andrew Gelman said...

Thomas:

Your remark at the end about "systems of knowledge" is interesting to me because it reminds me of the idea that racism is a framework, not a theory. It's a bit different--"men walked on the moon" is a statement which is either true or false (indeed, it's true), whereas racism is neither true nor false but rather is a way of looking at the world--but I see similarities, in the following steps:
1. The acceptance or denial of some fact or claim.
2. The construction of a framework (or use of an existing framework) that explains the conclusion in step 1.
Steps 1 and 2, of course, also characterize science (and social science). But in discussions of science (and social science) often seem confused to me because they don't distinguish between theories and frameworks. Hence you get pointless arguments about whether evolution is true, etc.

Thomas said...

Hi Andrew, yes, that's an important point. "Conspiracy theory" is actually a misnomer too, I guess. Conspiracism is a framework, not a theory. And perhaps this answers my implicit question at the end: how can someone who doesn't believe we landed on the Moon know anything? At first pass, we might think they are completely impervious to facts, but, once we understand their framework, we see how they can make sense of the world in a way that, for practical everyday purposes, works as well as ours. A flat Earther can get to Paris. A birther can have a sensible foreign policy. Maybe Wittgenstein is too quick to judge a whole "system of knowledge" by reference to a particular fact that he happens to believe.