The argument then moves forward to form a two-part mousetrap, and then a one-part.
But wait! Evolution is supposed to go from simple to complex, not the other way around. We should consider how “evolution” is possible from the one-part, then to 2-parts, 3-parts and all the way to the 5-parts mousetrap. Recall that evolution claims that the increase in complexity of biological systems is caused by random mutations. If the change increases the success of survival, then such change will stay in the population as described by natural selection.
Therefore, the analogy should proceed as follows: a one-part mousetrap is somehow formed. Then it becomes two-part as mutation randomly created the second part and randomly assembled it perfectly. This two-part mousetrap is more efficient and helps survival, so it stays in the population. Similarly, it proceeds to become 3-parts, then to 4-parts, and finally to 5-parts.
Let’s consider how the 3-parts mousetrap “evolves” into a 4-parts mousetrap. Of course, we cannot really see a simple mousetrap evolve into a more complicated mousetrap in a living organism. However, it should not be too hard to understand how similar arguments behind the analogy applied to biological systems. The argument follows closely to that of the author of “irreducible complexity” in his response to this same question.
To go from a 3-parts to a 4-parts mousetrap, we need the following: the hammer has to be bent and lengthened, with an additional extra segment appended to it. Two new pieces need to be created – a hold-down bar and a staple to put the bar in the ready-position. The end of the hold-down bar needs to develop a closed curl for the staple to hold on. The spring that works for the 3-parts mousetrap needs to be adjusted and fine-tuned to be useful in the new configuration for the 4-parts mousetrap.
Can a simple random mutation do all of the above changes to turn the 3-parts trap into a 4-parts trap? These changes have to take place at the same time and at the precise positions, otherwise none of the changes are useful and natural selection would have no reason to let it stay in the population. In other words, this set of changes – to turn a 3-parts trap into a 4-parts trap – is by itself irreducibly complex! Can we imagine how we can start from one-part all the way to the 5-parts mousetrap?
It seems only possible to “evolve” the final 5-parts mousetrap from a one-part mousetrap if it is designed that way from the beginning. Actually, that is how the less-than-five-parts mousetrap was described from the beginning! The author of that argument starts from the 5-parts trap, and mechanically simplified it until he reached a one-part trap. The 4-parts trap was designed from the 5-parts trap, and the 3-parts was designed from the 2-parts and so on. However, the idea of “design” is altogether unacceptable in Evolution.
Friends, if creating a simple mousetrap requires an intelligent being – a human in this case – to design, then how much more it is for the amazing molecular structures, which are billions times more complicated than the mousetrap, to require a designer?
A summary of the arguments for and against irreducible complexity can be found here.
