Thursday, May 17, 2012

Proof by Logic


When it comes to apologetics, there's one particular phenomenon that pops up quite frequently.

I call it, "logic-ing God into existence", or "proof by logic".

Devoid of any empirical confirmation, apologists attempt to prove that god exists by mere argument.

The Short Version

In case you don't want to read through my breakdown later, here's the short version.

Deductive logical arguments rely on premises being absolutely true in order to prove the conclusion. For instance, if you state that "Something can't come from nothing" as a premise, you have to demonstrate that premise as true by investigating everything in existence, that has ever existed, and make sure they all didn't come from nothing. Deductive arguments cannot operate on assumptions.

Otherwise, you're making an inductive argument, otherwise known as a "probabilistic" argument, where you're saying "everything we've checked so far hasn't come from nothing", so therefore it's unlikely that something in particular did.

Apologists frequently use deductive arguments with flawed and unproven premises to "prove" God, and their arguments fail. They can use inductive equivalents to those arguments, but in order to "prove" the conclusion, they need to empirically demonstrate the conclusion as the final step. They never do this, and their inductive arguments fail. 

Induction is primarily how we investigate, and helps lead us to the correct answers, but requires confirmation to bring the investigation to completion. For instance, compare apologetics to science, where assertions aren't accepted as true until they've been empirically confirmed, such as Einstein's General Relativity, which the scientific community didn't accept as true until it was demonstrated during a solar eclipse in 1919. Apologists skip that step.

They can't simply "logic God into existence". It needs to be demonstrated.

Now for the more detailed discussion...

The Long Version

Background in Logic

Two basic types of logic exist - deductive and inductive. Here's a crude introduction.

Deductive Logic

Deductive logic is reasoned arguments where given true premises are used to reach necesarily true conclusions. They're fairly absolute. 

This is a common example:
  1. All men are mortal
  2. Socrates is a man
  3. Therefore - Socrates is mortal
These arguments don't work if any of the premises aren't absolutely true:
  1. All men are mortal
  2. We're pretty sure Socrates is a man
  3. Therefore - Socrates is mortal
One would fine deductive arguments mostly in math, since it's very difficult to get absolute certainty in logical premises.

If the premises aren't absolute, and are more probabilistic, then we've generated a second type of logical argument.

Inductive Logic

Inductive logic might be better known as "probabilistic" logic - where we're making generalized assessments based on trends. For instance,
  1. Most swans are white
  2. John has a swan
  3. Therefore, John's swan is probably white
That's the approach we typically take in life towards most reasoning. We have data about reality and we determine likely conclusions. The premises don't have to be absolutely true for the conclusion to be reasonably accurate.

Problems with deductive logic

Apologists will frequently make deductive syllogistic arguments instead of probabilistic inductive ones. As applied to reality, these types of arguments are rife with problems.

Consider a deductive version of the swan argument:
  1. All swans are white
  2. John has a swan
  3. Therefore, John's swan is white
On the surface, it still seems reasonable, but there's a problem. Even if we were to spray paint a swan green, according to this syllogism, that would be impossible. Remember, all swans are white. There's no room for interpretation or excuses. All swans are white. The only way we could rationalized a spray painted swan is to say it isn't a swan.

Clearly, this premise isn't true, since we can spray paint it green. After that, the argument breaks down, and  becomes the aforementioned probabilistic inductive argument that we're more used to.

Further, let's say we didn't spray paint the swan green, how can we know that all swans are white? Did we check them all? Was it only the swans we observed that were white? For all we know there's some breed of swans in a neighboring country that are brown. 

We can't really validate this premise until all swans everywhere in existence are confirmed white. All of them. These are essentially unprovable premises. If the deductive argument has even one unproved premise, the argument fails.

That's why it's really hard to apply deductive arguments to reality, unless the premises are simple self-evident claims that are essentially useless upon themselves.


Let us examine another claim that bursts forth from the ether of the interwebs:
  1. Something can't come from nothing
  2. The universe is something
  3. Therefore, the universe couldn't come from nothing
Superficially, it seems relatively straight forward, right? Most people would consider this a "no duh" argument. Look a little closer - do any of the premises seem familiar?

It's that danged premise #1 again. Do we know that something can't come from nothing? How do we know? Did we check everything in existence to make sure it came from something? It may be that only the swans we checked so far that are white.

The inductive version is fine:
  1. As far as we know, something can't come from nothing
  2. The universe is something
  3. Therefore, the universe probably didn't come from nothing
The full fledged version of this argument, or the Kalam Cosmological Argument, makes a similar argument to the deductive version, and many claim that this proves God.

Hopefully you can see why it fails. Cosmological arguments aren't the only place where this breakdown occurs. Take, for instance, the Argument from Beauty (As I understand it):
  1. Naturalism cannot account for beauty
  2. Beauty exists
  3. Therefore, something beyond naturalism has to account for it - supernaturalism
  4. Further, beauty occurs in a mind, so it would have to be a supernatural mind
  5. God is a supernatural mind
  6. Therefore, God exists to be the supernatural source of beauty
Oh boy, are some of those premises questionable. That's typically where these arguments break down - one or more of the premises are touted as being true without being demonstrated or, in many cases, straight up false

Common sense extrapolation

Most frequently, however, the failure lies in the unknown - other possibilities and options that we're not even aware of yet. This is especially true in science - where "the truth is stranger than fiction". 

All our laws of physics break down at singularities (black holes, Big Bang, etc). The context gets so bizarre that our minds might not be able to grasp what truth is - even if it a perfectly natural phenomenon.

Apologists will use "common sense" (I'll have to tear into that in another topic) to extrapolate possibilities into unknown areas. That's normal. That's how we investigate. That's what gives us direction into learning about new things.

They don't stop there. This "common sense extrapolation" is then cast as being an absolute truth. Let's consider the infinite-Earth argument:
  1. The Earth is flat
  2. The Earth has oceans
  3. If the Earth had edges, the water would have drained off long ago.
  4. Therefore, the lands of Earth extend infinitely outward.
Most of us would disagree with premise #1 - but if one were to stand on a mountain and look all around, one would see a flat Earth. This intuitive understanding of the world is just common sense, so it may as well be a true premise, right? Also, it's possible there's a force field keeping the water in, or maybe the oceans are surrounded by lands that keep the water in. Or maybe the waters extend infinitely out and Earth is like a cluster of islands. The possibilities are endless.

Again, the deductive argument fails. So what do we do? What do we do when we're trying to figure out something new and bizarre, like the beginning of the universe, or the manifestation of beauty? Inductive arguments will only get us so far in figuring out possible conclusions.

What do we do?

Bringing it home


Demonstration is the answer. Empirical verification of the conclusion.
  1. All the swans we know are white
  2. John has a swan
  3. Therefore, John's swan is probably white
Once we have this reasoned induction, what do we do? Examine the swan.

Yep, it's white. If it's not, then we have to go back and change our first premise for future investigations.
  1. Most swans are white
Demonstration is what bridges the gap between probabilistic argument and knowledge. That's what apologists lack at every turn. 

They'll metaphorically give the infinite-Earth argument, and then stop, thinking they just proved that the Earth is infinite. There's no attempt to confirm it, no attempt to verify. They're done.

They do the same thing with cosmological arguments, ontological arguments, transcendental arguments, etc.

Deductive arguments are practically useless in practical reality, and inductive arguments require empirical confirmation.

They don't bother with empirical confirmation, and they head on home having just made an incomplete attempt at proving God, never realizing that the job isn't done.

As far as the apologists are concerned - they made their argument - and poof! God exists. 

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