### Author Topic: Basic Logic  (Read 2366 times)

#### Numsgil

• Bot God
• Posts: 7725
##### Basic Logic
« on: March 08, 2005, 05:19:33 PM »
It's come to my attention that not everyone here is familiar with basic logic.  Some have even gone so far as to rationalize their preconceptions with home grown 'logic' that suffers from logical fallacies.

Here's a primer course on logic.

Second, we should be aware of what is known as the 'Null Hypothesis'.  Here you go!.  And here you go again.

Last, understand how science works.  It does not say 'this is right'.  It says 'this sure fits all the data better than any other thing anyone's come up with (and is older than any new theories that explain the data equally well)'.

Here's how it works!

Check out the list of logic fallacies in the first link on logic I gave.  Bonus points to anyone who catches me in a logical fallacy and names it.
« Last Edit: March 08, 2005, 05:45:58 PM by Numsgil »

#### Numsgil

• Bot God
• Posts: 7725
##### Basic Logic
« Reply #1 on: March 08, 2005, 05:37:35 PM »
Here's an example:

Most of zelos's arguments suffer from Argumentum ad ignorantiam.

Specifically, "The fallacy occurs when it's argued that something must be true, simply because it hasn't been proved false. Or, equivalently, when it is argued that something must be false because it hasn't been proved true."

#### PurpleYouko

• Bot God
• Posts: 2556
##### Basic Logic
« Reply #2 on: March 08, 2005, 05:57:22 PM »
Also note that in any kind of science, the only truth is an observed fact.

(An example of an observed fact would be that a rock falls when you let go of it.)

From these observed facts we develop a hypothesis which we use to predict an outcome of a given experiment.

(The hypothesis drawn from the observed fact above would be that force is acting on the rock to make it drop)

As more and more of these predictions are fulfilled, the level of confidence in our hypothesis grows until at some undefined point it passes through a mystical doorway to the vaunted heights of a THEORY

(and such is born the theory of gravity)

Even after this, bits can be added or taken away provided that the general premise remains unchanged.

In order for something to be a scientific theory it must be FALSIFIABLE

That is to say that it must make testable predictions which can be verified or falsified by the outcome of the experiment.

That is science in a nutshell for those of you who can't be bothered to wade through Num's link.

:D  PY  :D
« Last Edit: March 08, 2005, 06:00:01 PM by PurpleYouko »
There are 10 kinds of people in the world
Those who understand binary.
and those who don't

PY

#### shvarz

• Bot God
• Posts: 1341
##### Basic Logic
« Reply #3 on: March 08, 2005, 06:54:46 PM »
Hey PY, are you familiar with Godel's theorem of undefinability of truth?  Basically, in any axiomatic system it is possible to create a statement equivalent to "I am lying", therefore creating liar's paradox and discrediting the system.
How is that for basc logic?  :)  Sends it to hell, I say  B)
"Never underestimate the power of stupid things in big numbers" - Serious Sam

#### Endy

• Bot Overlord
• Posts: 852
##### Basic Logic
« Reply #4 on: March 08, 2005, 09:51:26 PM »
Or the guy is simply lying about lying. :D

Endy B)

#### Numsgil

• Bot God
• Posts: 7725
##### Basic Logic
« Reply #5 on: March 09, 2005, 03:23:14 AM »

Quote
At this point, I'm going to jump all the way to the end of Gödel's proof, and fill in the middle later. (Thought all math was linear, didn't you?) The critical step is to take the following statement, which Hofstadter calls "sentence G," and translate it into a TNT-string.

Sentence G: This statement is not a theorem of TNT.

Now, ask yourself this question: is sentence G true or false?

If sentence G is false, then it is a theorem of TNT. Then we have a valid theorem which is false, and the whole system falls apart.

So it must be true. But if it is true, then it is not a theorem of TNT. Which means that sentence G is true, but it is not provable within TNT. That is Gödel's "incompleteness." He showed that TNT, although it may be perfectly consistent and always correct, cannot possibly prove every true statement about number theory; there is always something which is true, which the system cannot prove. So we're done!

Godel's theorem then doesn't say that you can discredit a system this way, just that any system must be incomplete, because you can arrive at statements that are true but unprovable.

That doesn't affect the creduility of any statements that are both true and provable from within the system.
« Last Edit: March 09, 2005, 03:23:59 AM by Numsgil »

#### PurpleYouko

• Bot God
• Posts: 2556
##### Basic Logic
« Reply #6 on: March 09, 2005, 09:18:56 AM »
Quote
Hey PY, are you familiar with Godel's theorem of undefinability of truth? Basically, in any axiomatic system it is possible to create a statement equivalent to "I am lying", therefore creating liar's paradox and discrediting the system.
How is that for basc logic?  Sends it to hell, I say

This only applies to our interpretation of the truth, not to the actual truth.

If an event occurs then it occurs. You might say it happened one way and I might say it happened another way but the only way it actually did happen is in its own way.

That is the kind of truth I am talking about.

A theory is never true, only an event can be.

:D  PY  :D
There are 10 kinds of people in the world
Those who understand binary.
and those who don't

PY

#### SyndLig

• Bot Neophyte
• Posts: 36
##### Basic Logic
« Reply #7 on: March 09, 2005, 11:29:59 AM »
We could all fall upon the theory that the universe doesn't really exist, and is the figment of the imagination of one being somewhere within the universe.

Of course, I'm also just a loon.  :)