Thursday, February 16, 2006
The Limits Of Science
Yesterday, I said
Let's consider Newtonian gravitation for a minute. Under Newton's laws, which I have previously described as the "hardest" of science, we learn that if I drop a feather and a bowling ball from the top of a building they will hit the ground at the same time. This is because acceleration due to gravity is a constant, not dependent on mass. But try, go ahead, I'll wait. Didn't work did it? Why?
This is a classic example, anybody who has studied science for a minute or two has been confronted with this problem. The answer lies not with a bad law of gravity, but with interfering forces, in this case the resistance of the feather to air, friction. In college I actually did this experiment in a vacuum, removing the air friction, and you know what? They did hit bottom at the same time.
This illustrates an important concept in traditional science - we define and study closed systems. That is to say, we try to strip away the interfering and competing forces to isolate the thing we want to study and understand precisely how it works. That is the real value of a laboratory, it is a place where the system can be carefully boundaried and controlled. We have pretty good, complete knowledge under those circumstances.
But doing science in the real world is a whole different story. Let's say we want to build a bridge. This is a realitivly straghtforward application of Newton. So, if we know so much how come things like the Tacoma Narrows Bridge happen? Because real world systems are not closed and carefully bounded like they are in the laboratory.
When we do real world science, like building a bridge, we are quickly reduced to doing things like "making allowances" and "padding tolerances." These terms are little more than making educated guesses about what we do not know. Thus in the Tacoma Narrows case, they neglected to make an educated guess about wind dynamics, and oops. There is a lot we do not know, even in the hardest of science.
Let's look for a moment a something a bit more obscure - Quantum Mechanics. This is the science that explains the behavior of things very tiny, electrons and protons and neutrons, and atoms and molecules. Again, we begin with the simplest system - a hydrogen atom, one proton and one electron. About this system, we know a lot, enormous amounts. We can tell you how such an atom will behave in a amazing and complex detail. Only one problem, try and find such a hydrogen atom in nature. It's almost impossible except in truly extraordinary places like the interior of a star! Nope, terrestrially, hydrogen really likes to hang around as a molecule consisting of two hydrogen atoms. How much do we know about that hydrogen molecule?
Well quite a bit, but not as much as you might think. Now, I will admit that it has been 20 years since I last checked, but when I did last check we could not calculate precise answers for the hydrogen molecule. See here is the problem, when we try, the equations get so complicated we cannot solve them. So, we resort to a technique called "numerical approximation." I would have to teach you a whole bunch of calculus to explain exactly what numerical approximation is, but let's put it this way - it is a mathematical technique by which we can come up with an answer to an equation that is not exact, but is usually good enough. Basically, it means lots and lots of computing power. It is a mathematical art known before the advent of the computer, but brought into its own when that device took away the need for highly educated armies, or a complete lack of a personal life, to actually do it
So, what am I saying here, in the much vaunted quantum mechanics we can only get the precise and absolutely correct answer for one system and one system only, and that is a system we do not typically encounter on a routine earthly basis.
So, you see, in the end, science knows with practical certainty very little. We are able to use what we do know as a basis for estimating and assuming and projecting to more practical problems, but that is something very different indeed for truly knowing and understanding something.
The next time someone tells you science proves there is no God, you might want to remind them of the genuine limits of science. Science knows very little with absolute certainty. "Science" as it is portrayed today has gotten awfully big for its britches. Maybe it is time we knocked it down a peg or two.
Related Tags: science, theory, knowledge, certainty, estimation
Most people view science with a superstious awe historically reserved for religion, out of simple ignorance. They don't know how it works, it looks like miracles.Upon reflection on that I thought it would be useful to talk about how little science really knows. This is a topic best looked at by example.
Let's consider Newtonian gravitation for a minute. Under Newton's laws, which I have previously described as the "hardest" of science, we learn that if I drop a feather and a bowling ball from the top of a building they will hit the ground at the same time. This is because acceleration due to gravity is a constant, not dependent on mass. But try, go ahead, I'll wait. Didn't work did it? Why?
This is a classic example, anybody who has studied science for a minute or two has been confronted with this problem. The answer lies not with a bad law of gravity, but with interfering forces, in this case the resistance of the feather to air, friction. In college I actually did this experiment in a vacuum, removing the air friction, and you know what? They did hit bottom at the same time.
This illustrates an important concept in traditional science - we define and study closed systems. That is to say, we try to strip away the interfering and competing forces to isolate the thing we want to study and understand precisely how it works. That is the real value of a laboratory, it is a place where the system can be carefully boundaried and controlled. We have pretty good, complete knowledge under those circumstances.
But doing science in the real world is a whole different story. Let's say we want to build a bridge. This is a realitivly straghtforward application of Newton. So, if we know so much how come things like the Tacoma Narrows Bridge happen? Because real world systems are not closed and carefully bounded like they are in the laboratory.
When we do real world science, like building a bridge, we are quickly reduced to doing things like "making allowances" and "padding tolerances." These terms are little more than making educated guesses about what we do not know. Thus in the Tacoma Narrows case, they neglected to make an educated guess about wind dynamics, and oops. There is a lot we do not know, even in the hardest of science.
Let's look for a moment a something a bit more obscure - Quantum Mechanics. This is the science that explains the behavior of things very tiny, electrons and protons and neutrons, and atoms and molecules. Again, we begin with the simplest system - a hydrogen atom, one proton and one electron. About this system, we know a lot, enormous amounts. We can tell you how such an atom will behave in a amazing and complex detail. Only one problem, try and find such a hydrogen atom in nature. It's almost impossible except in truly extraordinary places like the interior of a star! Nope, terrestrially, hydrogen really likes to hang around as a molecule consisting of two hydrogen atoms. How much do we know about that hydrogen molecule?
Well quite a bit, but not as much as you might think. Now, I will admit that it has been 20 years since I last checked, but when I did last check we could not calculate precise answers for the hydrogen molecule. See here is the problem, when we try, the equations get so complicated we cannot solve them. So, we resort to a technique called "numerical approximation." I would have to teach you a whole bunch of calculus to explain exactly what numerical approximation is, but let's put it this way - it is a mathematical technique by which we can come up with an answer to an equation that is not exact, but is usually good enough. Basically, it means lots and lots of computing power. It is a mathematical art known before the advent of the computer, but brought into its own when that device took away the need for highly educated armies, or a complete lack of a personal life, to actually do it
So, what am I saying here, in the much vaunted quantum mechanics we can only get the precise and absolutely correct answer for one system and one system only, and that is a system we do not typically encounter on a routine earthly basis.
So, you see, in the end, science knows with practical certainty very little. We are able to use what we do know as a basis for estimating and assuming and projecting to more practical problems, but that is something very different indeed for truly knowing and understanding something.
The next time someone tells you science proves there is no God, you might want to remind them of the genuine limits of science. Science knows very little with absolute certainty. "Science" as it is portrayed today has gotten awfully big for its britches. Maybe it is time we knocked it down a peg or two.
Related Tags: science, theory, knowledge, certainty, estimation
