Pre Science lecture: Is anything ever settled in science?
Before starting off on my science lecture series, the first installment of which will be about basic thermodynamics, I feel the need to write a bit about a standard misconception of science.
Many people get the false idea, that nothing is ever settled in science. To this, I have to ask, are we certain that the Earth is not flat or not?
I think that is pretty well settled. Yet, scientists talk about what is and is not certain in science with a vengeance. The issue here is that when a scientist is talking about what is not settled, (s)he is talking about something technical. The scientist is talking about the limitations of a measurement, or the limitations of a model.
For example, how much do you weigh? Do you know it to within +/- 5 lbs? For some applications, you might want to know to the gram. This is a limitation on measurement. Another limitation on measurement is say you only have one measurement, and you are not certain you have the best scale - you know that old one that tells you that you only weigh 120 lbs… To get a solid measurement, you need more than one and preferably from really well tested and calibrated equipment!
Another, more subtle limitation, is on models. For example, people like to quip that Newton was wrong and was replaced by Einstein. They have some picture that someday, Einstein will be replaced too, and that therefore, nothing is ever really “right” in science. If nothing is ever right, you can’t go wrong by assuming it is all crap…
But that is not how it works. All of the things that Newton got right, and were observed to be correct, still happened. Einstein did not replace Newton. He refined him.
Newton’s physics is all the mechanics you will ever need to put a man on he moon, calculate most orbits, and figure out golf-balls, motor cars, and tennis. Over three hundred years on, we still teach it for very good reason. Some really think that all of that stuff about force and energy and momentum just evaporated. Some think that because Einstein’s Special and General Relativity modify Newton, the nearly uncountable number of cases that have been observed to be completely consistent with Newton, no longer count.
People have a misguided idea that somehow Newton was wrong. After all, wasn’t Einstein smarter and more modern? Isn’t science always changing?
Well yes it is, but not in that way.
It turns out that for speeds close to the speed of light, or in intense gravitational fields, Newton’s equations need to be modified to include relativistic effects. However, if you aren’t going at close to the speed of light or dealing with a large gravitational field, those effects are simply too small to matter, and no instruments in Newton’s day could have directly observed them.
Einstein’s equations contain Newton’s equations. Newton’s equations are a limit of Einstein’s in the mathematical sense. In plain English, at speeds that are small compared to light, Einstein’s equations become Newton’s equations. They are still there even with Einstein. They will still be there in any future theory. What Einstein did was look someplace that Newton didn’t look. He added to Newton. He did not replace Newton.
I want people not to be fooled, or taken in by the dishonest sophistry of ignorant propagandists.
In this case, the smoke and mirrors about science being settled is a potent propaganda weapon for frauds, charlatans, and politicians. People want to believe what they want to believe. This gives them room to discount science that they do not like by doubting it unjustly.
Charlatans prey on this confusion to sow doubt against science they do not like. Historically, this has been to benefit tobacco companies by confusing people if the science was clear or not about cigarettes being bad for you, or fundamentalists confusing the issues of evolution. Recently added to this list are frauds and charlatans who work for fossil fuel companies, and their pet politicians who would confuse the issues of AGW. It is all smoke and mirrors based on the false notion that science doesn’t ever really know anything. Hope springs eternal! If nothing is correct, or ever settled, then you don’t need to worry about any science you don’t like for whatever reason, be it religious, in the case of evolution, or simple corporate greed that doesn’t worry about endangering lives, in the case of tobacco and AGW.
On a purely philosophical level, science is never settled. There is always room to take a better measurement or to refine a model. There is always room to look in the places where your models don’t have an answer, or simply have not looked, like when Einstein looked at relativistic effects and looked where Newton did not.
Yet, there is the real world of collected observations, taken from different researchers using different avenues of pursuit, that make a consistent picture. Since the picture was formed in so many different ways by so many different people, it becomes very difficult for the picture to be anything else and still be consistent with everything that has been observed. Such things can and do, for all intents and purposes, outside of the purely philosophical, indeed get settled.
What I mean by that is that certain things have so very much observation behind them that one approaches what I will call a Cartesian limit.
By a Cartesian limit, I mean that the only way that all of those observations from so many different sources and tracks of understanding could all be consistently lying to us, is if we were actually living in a world that was dominated by something fooling all of our senses and instruments all of the time. The “evil genius” of Descartes would be the “real story.” In more pedestrian terms, the only way that the “real world” could be different than all the data and observation we have, is if we were all living in the Matrix - and whatever the Matrix tells about all of the physics we see is a lie.
An example of this might be the notion that the Earth is round.
There is no new discovery, short of something that invalidates almost all other discoveries, that could possibly change that. If that weren’t true, then everything we know about ship masts disappearing last over the horizon, the satellite pictures of a round Earth, the fact that it is night in other parts of the world when it is day here would also be false somehow. Geometry itself would cease to work.
Another example might be that the Earth orbits the sun. Again, the only way for that not to be true, given all of the evidence that we have of it being true, would be if everything, and by everything, I mean literally everything, else we know of physics was a lie. Consider that for moment. If it turned out that the sun really was not the center of the solar system, then everything we know about energy and momentum conservation would be wrong. Everything we know about gravity would be wrong. We could never have put a man on the moon, or launched a myriad of satellites into orbit. All the engineering that went into making your car’s breaks work would have been a lie, Baseball could not be played, because baseballs would certainly fly differently. All sorts of things we know to be true could no longer possibly be true.
Another example is that evolution happened. If that were not true, then what we know of comparative genetics, comparative physiology, embryology, stem cells, anti-biotic resistant bacteria, the mutating flu virus, the fossil record and zoology would be wrong.
Another example is that CO2 is a greenhouse gas, and that adding it to the Earth’s atmosphere will raise the planet’s temperature. If that were not true, again energy conservation would be wrong. So would quantum mechanics, thermodynamics and the basic observation that putting on a blanket keeps you warmer.
So, as a purely philosophical argument, which is ever used by dishonest people to hide the truth, yes indeed, science is never fully settled. There is always room to refine a model - in a way that does not contradict all the data you already have! There is always a better way to make a more accurate measurement. However, for many things, the only practical or realistic way you would ever be able to fundamentally change the picture we have, is if we were all disembodied brains, floating in tanks somewhere, being fed a virtual reality that completely fools our senses and makes us experience a false virtual world. In this world we perceive though, what new thing could possibly be discovered that would make the Earth flat?
You could argue Cartesian Doubt all day. We really might be floating brains stimulated by the lies of a virtual reality (or something equivalent). However, it is very unlikely, impossible to prove or disprove, not science and certainly useless to debate. For those who like to get lost in Cartesian doubt, I say stub your toe. It hurts doesn’t it? The pain is as real as it needs to be.
Those who think that confusing Cartesian doubt with science is clever are only trying to tear down science. But that is what they do anyway isn’t it?