Friday, April 14, 2006

Faux Logic, Part V

Evidence Is Seldom Unambiguous

We slide conveniently between the words evidence and proof. When we hold an idea ourselves, it is seldom on the basis of proof, but because we believe the evidence weighs in favor of that idea. Yet we demand proof from those we dispute with. Unless someone produces an argument which compels us to change our minds, we hold to our previous idea. Those we argue with, frustratingly, demand the same from us.

Proof is seldom available. Even in mathematics, the usual gold standard in everyday conversation, proofs are contextual. Change the base, change the surface, and your elegant proof evaporates.

There is evidence for all kinds of propositions, including many that are not true. A person may be innocent of murder even though he owned the murder weapon and hid it, was known to be in the area, and had motive. I don't mean to merely say that "he was found Not Guilty;" he may be actually innocent.

Even when evidence is overwhelming in one direction, it is still usually mixed, and it is foolish to appear not to recognise this. Was communism a good idea? On one side of the scales are the 100-200 million people that communist governments killed, and the poverty of 90% of its citizens. It would take a great deal of evidence in the other direction to overcome that. But there is some evidence -- people put it forward all the time. They supported the arts of high culture, ballet and classical music. They made advances in opthamology. On a deeper level, does not suffering produce great literature? Isn't it worth something that they inspired people to reach for a more perfect world? Yes, these are all good things. They don't make much of a dent in accounting against all those dead people and poor peasants, but it's something.

Evidence can point in several directions at once as well. Say three people are exposed to a disease. One decides to pray, one decides to take medicine, and one decides to just wait it out. A week later, they are all well. This does not prove anyone's position. The evidence would weigh somewhat in favor of the third person -- they were all going to get well in a week no matter what -- but it's not proof by any means. One of the three might have actually caught a separate disease or an additional one; one of the first two may have had a peculiar susceptibility to the disease which should have killed him; the third person's mother may have been praying for him. Each can count the improvement in health as evidence. In none of the cases is it compelling evidence.

When we are trying to convince people of an idea we usually overstate the point for rhetorical effect. That's not contemptible if we recognise that's what we're doing. But it is intellectually dangerous, as we quickly come to believe ourselves. I have an uncle who sends me commentary from the hard left from time to time. "George Bush got us into a pointless war and has alienated the world." As a shorthand way of expressing that you believe that the president's actions were a major reason for military actions which have been a net loss, and have cost us more friends than we've made, the overdramatic statement is only mildly annoying. We can't spend all our time in discussion qualifying every point. But to take the statement as simple fact is just silly. As would be an opposing sentiment that "George Bush has saved America."

In religious or philosophical discussions, I am usually tempted to just not attend to people who make impossible pronouncements. "There's no more evidence for God than there is for the Easter Bunny." Well, there's not much difference in the amount of proof for either, but we've already established that proof isn't really the issue. As to the amount of evidence, the difference is profound. An individual might find the evidence for God insufficient, as there is no evidence that is unambiguously in favor of a deity. But when people try to claim that there is no evidence whatsoever, I suspect that something else is in play. Some need not to believe is ruling the intellect.


Petey said...

I'm impressed. You have just proven with no evidence that no evidence is really required to prove your point.

Steve said...

AVI, I've told you a million times not to exaggerate!

Did Abraham Lincoln exist?

Isn't postmodernism wonderful?

Is that Gagdad Bob's Petey?

Ymarsakar said...

Someone needs to clean up this infestation of "steves". There are way too many of them on blogger. I've seen 5, count them 5, on neo's comments section. Not at once, but in serial.

To get to the point, logic is either inductive or deductive. Since proof and evidence is part of induction, deduction is still independent of the contamination of good, bad, nonexistent evidence.

Ymarsakar said...

Therefore the superior form of reasoning is always based upon deduction, upon asking what Must be True instead of asking "What does the evidence purport to support as true".

AN advantage of studying philosophy.

Assistant Village Idiot said...

Proof's great when you can get it.

LiquidLifeHacker said...

Ha Ha...this 'could be' a conversation of a few lawyers sitting up at the bar!

*Just walking by on my way to the lady's room*

Anonymous said...

One can prove beyond doubt THAT God exists...but this won't change someone whose lifestyle is based on the presumption that a deity's existence doesn't MATTER.

On the other hand, some people are so invested in their ideology that proofs or 'criteria of credibility' don't matter so much as the continued health of the 'dream'...

For example, proofs abound that this chap, Osama Bin Laden is real, is currently at large, and is the head of an international terror organization responsible for several major attacks including 9-11-01.

But still there are those who insist he's 'really' an actor playing a part for the CIA and some cabal of BUSHITLER brownshirts who are the 'real enemies'. He can come out and say on live videotape that he's his own guy and threaten the West with utter destruction and these people will wink and nod and say "if this video helps Bush that PROVES OBL actually works for Bush..."

So, since Tojo's attack on Pearl Harbor helped FDR win in 1944, it's a lock that Japan was actually a soulless puppet of the evil US military-industrial complex all along?

There is no blindness like that among those who will not see...

OBloodyHell said...

> Proof is seldom available. Even in mathematics, the usual gold standard in everyday conversation, proofs are contextual. Change the base, change the surface, and your elegant proof evaporates.

Actually, math is independent of what you speak. At the heart of all math, however, are basic, given "conjectures", much like those inherent in high school geometry. Most are pretty inarguable, but, as in geometry there are usually some which are... "flexible"... we presume them but there is, in fact, no reason for that --- The Parallel Postulate is one such, and ties into the fact that all the angles of a triangle add up to 180, which leads to plane geometry.

Altering that fact, "all the angles add up to more than 180", leads to spherical geometry, which is useful in real-world celestial navigation. In it a "plane" is a sphere, not a flat surface we think of.

Flipping it the other way, "all angles add up to less than 180", leads to hyperbolic geometry, which has some advanced applications in modern physics. In this, a "plane" is sort of saddle shaped.

More interestingly, one encounters something called Godel's (that's a German "o" with two dots) Incompleteness Theorem, which says that it is impossible to come up with a system of axioms which do not allow for contradictions (such as the variations on the Parallel Postulate), to wit: "Can God make a rock so big he can't lift it?"