Logic: Reversing the Polarity

Logic: Reversing the Polarity January 1, 2015

There’s a type of argument that’s always bugged me. Some examples are:

  • Evidence for a god? It’s all around you. If God didn’t exist, we wouldn’t exist!
  • That hurricane was God’s wrath because we’re allowing people to happily live their lives in freedom [they probably wouldn’t put it that way]
  • Bob was a drug addict, and then went to church, and got better. That proves the power of the holy spirit.
  • Fine tuning proves God.

What I’d normally say is that you can’t demonstrate a proposed cause by observing its effects. You have to demonstrate that the asserted cause exists first, before it can be included as a causal mechanism. “You’re doing it backwards“, typically flies out of my mouth.

I think here’s another way of describing it. Suppose we had a loosely logical statement:

  1. Premise: During June, at Bob’s Apologetics Theme Park (The Unmoved Mover ride is awesome), one can get a free ice cream cone.
  2. Premise: It’s June
  3. Premise: We’re at Bob’s Apologetics Theme Park
  4. Conclusion: We can get a free ice cream cone

It’s true, we can get free ice cream if #1 and #2 are actually true. What the aforementioned apologists are doing is essentially reversing that.

  1. Premise: We got a free ice cream cone
  2. Conclusion: It’s June
  3. Conclusion: We’re at Bob’s Apologetics Theme Park

It doesn’t work in reverse. Most would recognize the error. It’s assuming that there’s only one path to the first conclusion (getting free ice cream). It’d only be reversible if the logical premises were “If, and only if“, which itself would need to be demonstrated.

The apologist argument is doing the same:

  1. Premise: If God exists, the universe will be finely tuned.
  2. Premise: God exists.
  3. Conclusion: The universe is finely tuned

But that’s not actually what they’re doing… they’re doing it backwards.

  1. Premise: The universe is finely tuned.
  2. Conclusion: God exists
  3. Conclusion: God finely tuned it

Just don’t get me started as to whether it’s actually “finely tuned.” Let’s just go with the broad notion that the physical constants are correct for life, and changing them would prevent life from existing (not that I buy that either).

Here’s another:

  1. Premise: If God exists, he would have written or inspired a holy book
  2. Premise: If God exists, he can see into the future (or however you want to put it)
  3. Premise: That holy book would have assertions about the future
  4. Premise: God exists
  5. Conclusion: The holy book will have assertions about the future that are true (or will have assertions from the past about the present that are true)

Reverse it!

  1. Premise: A holy book has assertions from the past, about the present, that are true
  2. Conclusion: God exists
  3. Conclusion: God can see into the future
  4. Conclusion: God wrote/inspired the holy book
  5. Conclusion: God informed assertions about the future

Does that sound familiar? Once again, the apologist is assuming only one path to the original conclusion, and here I discuss other possible paths that are actually much more likely.

Science does that, doesn’t it?

When we examine the “reversed” logical arguments, they do seem a lot like prediction, don’t they? Science does that all the time. Consider this:

  1. Premise: If evolution is true, we’d expect to find fossils
  2. Premise: Some of those fossils would be “transitional” (before you yell at me – specifically meaning, transitions between major distinct types of creatures, like land and sea dwelling)
  3. Premise: Some of those transitional forms would be between land and sea
  4. Premise: Evolution is true
  5. Conclusion: Semi-aquatic, semi-tetrapod fossils should exist

Reverse it!

  1. Premise: We discover Tiktaalik, a semi-aquatic, semi-tetrapod fossil
  2. Conclusion: Evolution is true
  3. Conclusion: Transitional forms exist
  4. Conclusion: Some transitional forms are semi-aquatic, semi-tetrapod
  5. Conclusion: Fossils exist (duh)

The creationist would say, “Yeah! Science is doing it too!” No, actually. I mean yes, but there’s much more to it.

Here’s the key difference – creationists and apologetics halt right at the reversed argument – full stop. No attempts at empirical confirmation ensue. No attempts at falsification ensue. No attempts at testing the predictive power ensue.

The apologist will conclude that he/she has proved his/her case at that instance… and is done. Science doesn’t.

Science is not syllogistic. It has a syllogistic compass… or a syllogistic dowsing rod, if you will. Logic acts as a guide to investigation. It’s a means to an end, but not the primary mechanism for validating a claim.

Prediction versus Postdiction

The primary difference between prediction and postdiction is that with prediction, we don’t know the results ahead of time.

Suppose there’s a light switch, and a light. It’s current state is that the switch is set to “on”, and the light is currently lit. This is our only information at this point – we just discovered the switch/light.

Postdiction would examine the existing information, and conclude that the switch toggles the light, because:

  1. Premise: If the switch is set to “on”, the light would be lit.
  2. Premise: The switch is set to “on”
  3. Conclusion: The light will be lit


  1. Premise: The light is lit
  2. Conclusion: The switch is set to “on”
  3. Conclusion: The switch toggles the light

This syllogism seems really vapid… almost a tautology. We can check and see that the reversed conclusion are actually true, and it just seems obvious. But what if there’s no connection between the two, and by coincidence (something apologists and creationists love to dismiss), the switch happened to be set to “on”?

Reality is a lot more muddy and convoluted than that. Suppose that switch was actually a 26-switch panel, each labelled by a letter, and this one was “F”. Suppose that there’s also motion sensors around, and other mechanisms, where our presence could have activated some mechanism for the light instead.

All of a sudden, that syllogism above seems to be naively oblivious to other possibilities. That’s how the bulk of apologetics operates, though. Everything from the cosmological arguments, fine-tuning arguments, arguments from morality, intelligent design, etc… all (though there may be some minor exceptions) operate on this principle of examining existing data, and ascribing speculative causes to them…. and then they’re done.

We have a solution for this – prediction.

We want to know whether Switch “F” toggles the light. We can predict something we don’t know ahead of time – toggling the switch between “on” and “off” should have a corresponding status change of the light, being lit and not-lit. You flip the switch several times, and see the expected outcomes.

Congratulations! You’ve now empirically confirmed a hypothesis. Even if there’s more to it than that, and the connection isn’t so clear-cut, you’ve now done more actual demonstration of your claims than the sum total of all Apologetics, ever conceived, in human history.

Clapping Captain

Prediction doesn’t require that the event take place in the future, though. It means that the results aren’t known ahead of time. Tiktaalik is an example of that. Given the data we had about evolutionary history, we expected to find something along those lines, in a particular geologic time frame, in particular regions. We then set out to test that hypothesis – and found the empirical confirmation.

Even then, science isn’t done. It’s an ongoing process to refine, revisit and retune existing models to best fit the available information that we have at the time.

Quality of Prediction

One might say that Biblical prophecy does this, but the primary problem with arguments from prophecy, is that the requirements are so open-ended, that the results inevitably come true, without the asserted causal mechanism needing to be real. They’re incredibly prone to Sharpshooter fallacies, confirmation bias, statistical probability, and breathtaking re-interpretation.

They’re technically predictions, but not meaningful ones. The more specific, and precise the assertion, the better quality the prediction. The equivalent evolution version would be something like “If any life form is different from its parent, at any point, evolution is true” or “At some point in the future, a descendant of this dog will be significantly different than its predecessors

Evolutionary predictions are exactingly specific and confirmable in comparison, and creationists still dismiss them, when they’re demonstrably true.

On the flipside, it’s possible for a proposed prediction is so vague and unbounded, that it’s not actually predicting a thing. It’s predicting any thing. At that point, it’s not qualifying as a serious “prediction” anymore.



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