A common complaint against falsification is the following: Imagine that you have two theories about building bridges. Theory A has been in use for 50 years and has never been falsified, whereas Theory B is brand new and completely untested. Which one are you going to use?
Presented this way everyone normally says, “Theory A, of course.” But let’s get under the hood of this argument and see what makes it tick and why it’s faulty.
First of all, it’s generally presented to a bunch of people (like you and me) who know nothing about bridge building. Except for once in physics class with a bunch of wood, I’ve never built a bridge. The bridge I built quickly failed under pressure because I didn’t know what I was doing (and was more concerned about just building something to get a grade anyway) and so except for the fact that my teacher said triangles were important for proper bridge building, I know little about building bridges.
So that’s the first problem with this argument: People are asking us to make a good decision about something we are completely ignorant of and/or advancing arguments that sound good and can confuse us when we’re talking about something we know zero about. You can easily go to http://www.garrettsbridges.com/building/bridge-joints/ and read about the proposed types of joints where one is supposedly stronger than another. A new bridge building joint theory would propose some new kind of connection (not previously dreamed of) or claim that lap joints are not really better than end joints in certain circumstances, right? Specifically what does the theory claim so that we can evaluate it?
Just putting this new theory into the mind of someone with expertise in building bridges would let it get evaluated right away because the person would think back over his experience and think, “No, I saw a bridge like that once and it didn’t work that well” or think “You know, I always wondered why John’s bridge carried more load than mine and now that I think about it, it did have that feature partially incorporated but more as an accident than by real design.”
So you see, all theories are immediately subjected to potential falsification by being compared to the past. A new gravitational theory that couldn’t explain why the planet Venus was moving in a specific way two weeks ago gets shot down on the spot. Obviously, therefore, all new theories are just as verified as the old theories in the sense that they will be compared against the same weight of experience the old theory had.
Let’s take a few hypothetical examples. Let’s say that theory A proposes that triangles make bridges strong and that circles should go around the triangles to keep them in place. Theory B claims that circles make the bridge strong and the triangles are only there to keep the circles in place. From a bridge builder point of view, it doesn’t matter which theory is right. The solution is still to build bridges with circles and triangles.
As another example, let’s say that theory B claims that triangles are not really the key, but rather half-rectangles are better and therefore the triangles should be arranged in such a way as to form rectangles to build stronger bridges. Won’t the proponent of the theory immediately point to some bridges not built according to his two-triangle forming a rectangle theory that failed as ‘proof’ of his theory? Of course he will. He will also point to bridges built according to his design that are still standing as proof that his new insight is superior.
The ‘new but untested bridge building theory’ argument is nothing but a red herring. Unless the people who claim this is possible can actually mention a specific time that this (or something like it) occurred, they are just throwing vague suppositions out in the dark.
On the other hand the proponents of falsification can point out specific times when induction failed. Mercury was supposed to move in a certain way and it didn’t. Believers in Newton Newton
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