Systemic Truth Pt. 3: Logic as belief: dropping modus ponens.
Earlier in this piece, I gave an example of a conversation between two people, in which one's argument referenced something along the line of "immutable scientific principles", essentially, "the way the world works" (TWTWW). The steps of the scientific method: Hypothesize, Test, Reconsider, Repeat, allow us to generate a stupendous amount of knowledge (within experimental and theoretical limits, of course).
So it might be fair to say that we can recognize the scientific method as THE de facto way of looking at the universe. After all, it is totally free of any grounding and it has produced everything known to man. Naturally, we might call the scientific method our "immutable scientific principles". In this way, we can explain the connection between the tides and the moon, and then why the moon is here, and then why a long time ago many larger objects may have orbited the sun, and then where the solar system came from, etc, etc. All this without ever doing anything outside of observing!
Many atheist-theist arguments break down, essentially, to the acceptance of the scientific method. Often, it is the case that a religious ideology contains a contradiction: for example it accepts that dogs and cats have more or less been evolved for domesticity, but not that humans have evolved as well.
So score one for the atheist, right? Not so fast. The line of reasoning here is as follows:
Note that contradiction is not compatible with scientific method
Observe that position Q is compatible with the scientific method, but P is incompatible with Q.
P is not compatible with the scientific method, and thus does not represent TWTWW.
Seems both sound and valid, right? But why can I just jump from 2 to 3? In order to do this, I need a seperate step:
3A: If P is incompatible with the scientific method, and only things provable with the scientific method are TWTWW, P is not TWTWW.
It will take a minute for this to make any sense. What I am doing here is challenging the most basic rule of inference, modus ponens.
Modus ponens says if we have the following:
This is usually the way we interpret arguments in their most simplest representation. However, modus ponens is something that needs to be "tacked on" to the scientific method to make it more robust! Now, the scientific method is not aloof and background independent, but it requires a very specific rule!
Consider a non-modus ponens argument.
What comes next? Well we need a rule to get from P to Q. Thus,
If (If P, then Q) and P, then Q
This formalizes our modus ponens assumption. But when we relax this, we still have more that is required, namely:
If (If(If P, then Q) and P, then Q) and If(If P, then Q) and P, then Q) and P), then Q.
And so on. By dropping the requirement of modus ponens, we note that nothing, in fact, can be shown to be anything in this way, and so our anti-theist argument can prove nothing without explicitly referencing a logical rule. Looking back to previous chapters here, we note that the scientific method therefore is a belief system which is using systemic truth to tell us TWTWW.
And so the important question here is: why must we believe modus ponens?
The simple answer is: because it is natural to us. However, even within the scientific method, we have many, many things that are at first unnatural. Why is modus ponens excepted?
Tomorrow, I'll try to explain this fully, and offer some examples of instances where modus ponens fails. If it isn't clear now, we're headed towards a formalization of the "belief system" that is scientific thought. We'll get there soon.
For a better treatment of the problem that of relaxing modus ponens, please see Lewis Carroll's "What the Tortoise said to Achilles"
