Essay:Explaining the fall of Popper
I am going to say this right now: I am no Philosopher of Science, or Historian of Science. I have some interest in the subjects, but that's about all. I'm writing this because it took me awhile to understand why Karl Popper was no longer the dominate figure in Philosophy of Science, but when it did hit me, it hit me like a ton of bricks, and I thought I'd like to help some others to understand the issue. But first, pedantry!
What did Popper think?
I'm not going to claim to be any kind of expert on this, so this is going to be a fairly brief overview of what Popper thought. The issue that Popper dealt with (that I'm responding to) is the simple question: What is science? This seems like a fairly easy question, but is one that has been dealt with for generations. The solution that Popper came up with was basically: falsification is what is science. Basically, come up with a theory (all things will fall towards the center of the Earth), and come up with a way to test it (I'll drop a pencil). Your theory suggested something would happen, and it did. So, your theory has support. As you continue to drop things you note that every time you drop a thing, it falls towards the center of the Earth. Therefore, your theory is correct as far you're aware. Congratulations! Now, what falsification is, is that if a theory could be done which shows an object that does not eventually fall towards the center of the Earth, your theory has been falsified. Since this is possible and you have done numerous experiments which all show that your theory is correct, you are being scientific.
However, we eventually got into space, and dropping things does not cause them to fall towards the center of the center of the Earth. This means your theory, in the strictest since, is incorrect. But, you can modify it to all objects fall inevitably towards the center of all other objects (I guess this is more along the lines of Newton, and not in line with our modern understanding of gravity, but that is besides the point entirely).
This theory-test-prove-counter example-modify is the basics of the scientific process as understood by Popper and scientists for years. And then, something happened.
What doesn't work under Popper?
Sadly, a lot. There are whole fields of science where it is virtually impossible to empirically test anything for one reason or another. In medical fields, you can make the argument (from a Popperist perspective) that we don't know, for example, that the virus we associate with gonorrhea causes the symptoms associated with gonorrhea, and that the only way we could know that is if we took someone who did not have gonorrhea, and give them the virus to see if they develop the symptoms. And then replicate this. A lot. This is of course hilariously unethical. So, instead we do the next best thing, of saying "I think that this virus causes gonorrhea, if we treat this virus, the symptoms clear up, so this virus causes gonorrhea". That is one where you can spend all day making arguments back and forth, but I won't focus on it.
Physics has been coming up with some interesting things to say lately about the nature of the universe. One is that the universe is expanding. The process behind this is complicated, but in short we are able to see the light as galaxies move, and this color is "tinted" (for lack of a better word) towards the red end of the light spectrum. Because of this, we know that the galaxies are moving away from us. The interpretation that is made about this is that all of the galaxies are moving away from everything else as the universe expands. But, aside from re-interpretating the same basic data, we have no way of testing that this is true. From a Popperist perspective, this is basically pseudoscience. Uh oh.
We also cannot test anything in climatography or meteorology (study of the atmosphere and weather). We cannot attempt to create a low pressure zone over warm ocean water at the convergance of a high pressure cell and a low pressure cell and try to create a hurricane. Both because we do not have anywhere near the technological ability to dream of how to do that, and because that would be incredibly unethical to try to do. Imagine if it made landfall somewhere! Geology is another example of this small problem, since we cannot do any studies on the Earth's core other then bouncing sound waves into it and guessing that because of where they come out of and their length that's pretty damn dense, and that that density is pretty similar to molten iron/nickle on top of solid iron/nickle.
Popper's views are so restrictive on what is science, that a lot of what we consider science is sloughed off as pseudo-science unnecessarily. This doesn't strictly make it bad, as when it comes right down to it, the scientific method of experiment and falsification is still king, but the king is often so overbearing that it's impossible to get any work done very often, so we turn to the next best thing, which is figuring out based on the information we have and the prior empirical tests what the hell is going on out in the wild world.