Ground truthing

I have liked the phrase "ground truth" since I first encountered it.  It comes from the early days of the space age.  I was a kid when Sputnik, the first artificial satellite, was launched.  The phrase "ground truth" comes from a little later.  Sputnik was primarily a publicity stunt.  It just beeped.  And it beeped in such a way that amateur radio enthusiasts could pick the beeps up and tell what direction they were coming from.  This meant that there was never any doubt that the Russians had launched an artificial satellite.

But Sputnik was quickly followed by satellites that actually did things.  And one of  the big things they did was measure things.  But what did the measurements mean?  That's where "ground truth" came in.  Scientists would take a look at some satellite measurement of something happening on the ground.  Then they would go out and see what was actually happening there.  That allowed them to be able to say "if the result of some satellite measurement is X then that means this specific thing is happening on the ground".  They were establishing the ground truth behind a satellite measurement.  That way they didn't have to assume they knew what a certain measurement meant, they would actually know.

And the business of being able to actually know is important tome.  So I periodically go out and try to establish the "ground truth" of something.  And this is not limited to satellite measurements.  It relates to anything.  If it looks like this what is it actually?  If you have performed a ground truth then you know.  So let's look at some of the ground truth efforts I have made.  You will see that this can be applied very broadly.

And let me start with an embarrassing but very enlightening moment that happened at about the time I was introduced to the phrase "ground truth".  At some point I learned that Galileo was the first to demonstrate that if you can ignore air resistance and the like then the flight of a cannonball follows a parabolic curve.  And the teacher put up a proof on the blackboard that this was true.  And the proof was pretty simple and straightforward.  Then he gave us Galileo's proof.  How hard could it be?

Well, it turned out to be extremely hard.  I never did really figure it all out.  Unlike the proof the teacher put up it was very complex, difficult, and hard to follow.  So what was going on?  It turns out that the mathematical tools Galileo had access to were very primitive.  They consisted primarily of Euclidian geometry.  If that's all the tools you have to work with then you have to be brilliant and persistent to come up with a proof.

In general this is a common situation.  The ancients look dumb to us.  They believed stuff we now know to be wrong and their "brilliant achievements" now seem pretty obvious and trivial.  But that's because we have a modern perspective.  And part of that modern perspective includes a lot of tools the ancients didn't have.  If you have Analytic Geometry then proving a cannonball follows a parabolic trajectory is pretty easy.  But Galileo didn't have Analytic Geometry.  So the most obvious thing I learned was Galileo was a really smart dude.  And that's a really important point.

Besides Galileo having only primitive mathematical tools at his disposal teachers have had hundreds of years to come up with a simple and straightforward way to prove something and that's what they now give us students.  But a whole lot of work has been put into these "simple" proofs by a whole lot of smart people.  There was no one before Galileo so if he didn't come up with it, it wasn't going to happen.  It is much easier to refine something someone else has created than it is to come up with it in the first place.  So since then I have had tremendous respect for whoever does something for the first time.  It's really hard.  If it was easy it would have already have been done.

I am not great at math but I am better than most people are.  So trying to make sense of Galileo's proof is definitely not most people's cup of tea.  But there are ways to ground truth things that are not so math heavy.  But before I get to them let me go to what I would call a "math light" example of ground truthing.

The Protestant Revolution is usually dated from when Martin Luther posted his "95 theses" on the front door of the that church in Wittenberg Germany. English translations of the document (it's not very long -- each thesis is just a sentence or two) are readily available on the Internet.  So I took a look at them.  And it was very instructive.  The document was a "proof" of a position Luther was taking.  Basically he was saying that the Catholic Church was doing something wrong (selling indulgences, if you care).

Now I agree with Luther that selling indulgences is bad and contrary to what the church has to say about good and evil.  But that was not what I wanted to know.  I wanted to know if Luther had proved what he set out to prove.  And much to my disappointment I decided he didn't.  And the problems were technical.  There is a certain way you operate when you are trying to prove something.  I thought his argument was incoherent and disorganized.  So its technical flaws meant it was not a proper proof.

Now, unlike in the Galileo case, I didn't have any problem following Luther's logic.  And I found no individual thesis problematic.  I just thought there were gaps in the proof that possibly could have been filled in but weren't.  To the extent that I could follow Galileo's proof I found no gaps.  It was a properly constructed proof.  I just couldn't follow it, at least given the amount of effort I was willing to invest.

What was enlightening about all this was that no one cared whether Luther's proof was flawed or not.  They only cared that it existed at all.  So at least on the Catholic Church side they didn't really think the truth of the matter was very important.  And unfortunately I find that the attitude of the Catholic Church at that time applies to pretty much all religious people pretty much all the time.  They just don't think the truth is very important.  Other things, typically faith, are far more important.

Now let me move on to something profoundly scientific but almost completely free of mathematics.  And that's evolution, at least the aspects of it that I am going to talk about.  The foundational document on the scientific side is On the Origin of Species by Charles Darwin.  This book is NOT a technical treaties designed to be read only by experts with specialist knowledge.  It was explicitly written to be read by average people who knew about things people of the time knew about like animal husbandry.  But understanding the book required no specialized expertise at all.  There is absolutely no scientific mumbo jumbo or high falootin math or anything else that would put off the average person. The language is now slightly archaic but not so much so that anybody living today can't read and understand what he has to say.

So I read the book a few years ago.  Well, I actually skipped past a number of portions.  (I'll explain why in a minute.)  Darwin was very clear about what he was saying and why he thought he had the right of it.  And most people don't know that the book went through several revisions.  Why?  Not because he bungled things or got them wrong.  Instead he carefully listened to people's objections and added additional material to clarify points that were being misunderstood and adding further evidence to show why this or that objection was wrong. And that's why I skipped large portions.  He went on and on belaboring a point just to make sure that people could see the amount of evidence available to back up what he was saying.  So I would go through the first part of the evidence, be convinced, and skip the further evidence he piled on at great length after that.

And a revelation to me was that the anti-evolution people have not come up with anything new in the roughly 150 years since the book was published.  Every few years somebody comes out with a "new" reason why Darwin was wrong.  But over and over you will find that Darwin addressed that point in nauseating detail either in the original version or in one of the updates.  But since the anti-evolution people don't bother to read the book they don't know this.

Let me move on to another example of "they didn't bother to read . . .".  What I'm talking about is gun rights and the whole Second Amendment thing.  The definitive case law on the subject is a US Supreme Court case called "Heller".  I wrote about all this in detail in a post all the way back in 2013.  You can find it here:  http://sigma5.blogspot.com/2013/01/second-amendment-rights.html.
It turns out you can read Supreme Court decisions online.  There is a link to the full text of the Heller decision in the previous post.  The majority and therefore prevailing opinion was written by Justice Scalia.  And the guts of his opinion, in my opinion, is a 2 page section (Section III) in which Justice Scalia says it is completely constitution to regulate fire arms.  He just says the regulations must be reasonable and then outlines what he sees as reasonable regulation.

So the Heller case is one of those "I know it when I see it" cases.  It is settled law that it is constitutionally permissible to reasonably regulate fire arms.  The whole argument is about what is "reasonable" and what isn't.  One person's reasonable is another's unreasonable and vice versa. So when I listen to someone on either side I try to determine if they understand this.  Unfortunately, I find very few people on the pro-gun side that understand this.  So I conclude that they haven't read Heller and don't know what they are talking about.  In other words, I ground truth them and they come up short.

I recommend everyone read the odd court decision.  I'm sure that there are obscure cases having to do with some arcane or obscure corner of this or that where I would have no clue as to what's going on without specialist expertise.  But I don't read those kinds of decisions.  Judges in the cases whose decisions I read are trying very hard to make what they have to say accessible to the general public and I think they almost entirely succeed.

I do cheat but only in one small way.  Decisions are littered with "citations", references to a decision on some earlier case.  I don't pay attention to the actual citation.  After making the citation the Judge will tell us why some aspect of that case is important to this one.  I just take it on faith that the Judge is honestly and correctly interpreting the previous case.  I have found that generally Judges do play fair on this.  And if they don't then I depend on the dissenting opinion to point this out to me.  By taking this shortcut I may get misled but if it happens it doesn't happen very often.  And that's good enough for me.

I have mentioned that I have taken a stab at reading Galileo's proof and had more success reading On the Origin of Species.  In general I like to dabble in the foundations of science.  I have read other documents from the history of science.  Some years ago I read Optics by Sir Isaac Newton.  I found it pretty readable.  It concerns the properties of light.  Newton did some experiments with prisms and lenses and was able to come to some profound conclusions.  I think Optics is pretty accessible to the average person.  His other and more important work is Philosophiae Naturalis Principia Mathematica (usually shortened to "Principia").  That is a heavy lift.  I am taking a second run at it but I do NOT recommend it to the average person.  I'm not sure I will be able to make my way all the way through it.  But I am going to give it a try.

Let me introduce my final suggestion by telling a story.  I used to read The Wall Street Journal In High School.  I know, that's weird.  But I did (and you don't have to).  But my point is this.  This was long enough ago that when I started reading the Journal the US ran a surplus balance of trade (flow of goods and services) and a surplus balance of payments (flow of money).  The Journal thought this was a good thing and got all up in arms when first the balance of trade and later the balance of payments went into deficit.  They argued that both of these were very bad.  And their arguments made perfect sense to me.

But then I waited.  The reason these were bad things was because they would inevitable result in other bad things happening to the US.  But somehow those other bad things never happened.  And the US has been running deficit balances with respect to both trade and payments for many decades now.  The bad things the Journal predicted never came to pass.  And that was a real lesson to me.  Remember their argument for why these developments (i.e. both trade and payments going from surplus to deficit) were completely convincing to me.  So there was nothing wrong with the argument except it ultimately turned out to be wrong.

So one of the things I look for is predictions.  The Journal predicted that bad things would happen.  That's good because that is a prediction and we can see if it comes to pass.  But it didn't come to pass and that means the initial argument has been cast into doubt.  I like predictions.  I mistrust anyone who believes so little in what they are saying that they will not make a prediction.  But a prediction is a two edged sword.  If it's right then kudos to the predictor.  But if it's wrong then a serious effort needs to be made to understand why the prediction didn't pan out.  I also mistrust people who won't admit it when a prediction goes wrong and then won't make a serious effort to understand why it went wrong.  I have seen little or nothing out of the financial community admitting that their predictions were wrong in these cases nor any analysis as to why they turned out to be wrong.

This thing I just talked about is something anyone can do.  All you have to do is note what predictions people make then let some time pass.  Then you go back and see whether the prediction panned out.  This is something the press should routinely do.  But they are erratic.  They sometimes will "go to the tape" and show someone predicting something that didn't pan out.  That's good but it is not enough.  They need to go the next step and that's no longer paying attention to someone who makes a lot of predictions that go wrong.  The press is about ratings.  They go with the people they think will generate ratings even if they have a demonstrated track record of getting it wrong.

This has gone on long enough that we are now in the situation where people flat our lie routinely.  Yet the press hangs on their every utterance because covering them is good for ratings.  And they don't contextualize them as known anti-experts (people who frequently get it wrong) or known liars.  People who don't have the time or inclination to keep track are left on their own.  And that has led to what can politely be called "confusion".

So everyone can engage in ground truthing.  In lots of areas it helps to have some mathematical ability.  But other areas do not require any mathematical ability.  No mathematical ability is required to read a legal opinion.  Reading legal opinions is a good way for figuring out who knows what they are talking about and who doesn't.  But you don't even need to do that.  You can jut play the memory game.  What did that person or group used to say and what are they saying now?  Republican back in the Cold War days were very proud of our open borders because walls are for oppressive Communist Regimes.  Now it's "build a wall" and "isn't Putin just great"?

But all this ground trothing is only important if knowing the truth is important.  If whatever your belief system tells you, what you have faith in, is more important than knowing what is true and what is false then ground truthing is counterproductive.  But if ground truthing is counterproductive then you don't get to use it to bolster your side of the argument.  You are either fact based or you are not.  You don't get to cherry pick.