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The Dumb Logic Thread

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steve_bank

Diabetic retinopathy and poor eyesight. Typos ...
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The science forum has the dumb question thread. This is for dumb logic. No need to srart a new thread for every idea. Lump it all together.

for example.

If a conclusion follows from a premise that is obviously absurd then the argument is structurally valid.

The Earth is flat and thin, so if I step off the edge I will possibly fall off and there is no air past the edge..
 
steve_bank said:
The science forum has the dumb question thread. This is for dumb logic. No need to srart a new thread for every idea. Lump it all together.

for example.

If a conclusion follows from a premise that is obviously absurd then the argument is structurally valid.

The Earth is flat and thin, so if I step off the edge I will possibly fall off and there is no air past the edge..
Click to expand...

That is a very interesting post.

I wish some expert on mathematical logic could comment.

To that effect, I would encourage you to explain why you think the argument is "structurally" valid.

In particular, why do you think the absurdity of the premise makes the argument ipso facto "structurally valid"? I never heard of that one before.
EB
 
steve_bank said:
The science forum has the dumb question thread. This is for dumb logic. No need to srart a new thread for every idea. Lump it all together.

for example.

If a conclusion follows from a premise that is obviously absurd then the argument is structurally valid.

The Earth is flat and thin, so if I step off the edge I will possibly fall off and there is no air past the edge..
Click to expand...

The If/then structure is more of an observation, than an argument. If I observe the Earth is flat, what is the list of possible following observations. If the Earth is flat, I will able to look over the edge and observe more.

All men are mortal.
Socrates is a man.
Therefore, all men are Socrates.
 
Darn it all to heck, looks like I made a dumb argument. But then that is the thread.
 
Bronzeage said:
steve_bank said:
The science forum has the dumb question thread. This is for dumb logic. No need to srart a new thread for every idea. Lump it all together.

for example.

If a conclusion follows from a premise that is obviously absurd then the argument is structurally valid.

The Earth is flat and thin, so if I step off the edge I will possibly fall off and there is no air past the edge..
Click to expand...

The If/then structure is more of an observation, than an argument. If I observe the Earth is flat, what is the list of possible following observations. If the Earth is flat, I will able to look over the edge and observe more.

All men are mortal.
Socrates is a man.
Therefore, all men are Socrates.
Click to expand...

if then else is part of logic. Conditional logic.

p1
p2
c1
c2
c3
c4

If p1 and p2 then ci or If p2 and not p1 then c2 or if not p1 and not p2 then c3 else c4.

Like algebra formal logic is a shorthand synbolic represention of verbal desriptions.

A & b is for me the Boolean AND or you might call it conjunction. The two variable truth table.

a & b = c
a b c
f f f
f t f
t f f
t t t

In words if a or b is false then c is false, if a and b are true then c is true.
 
Last edited:
p1 1 + 1 = 2
p2 1 + 1 = 3
c 1 + 1 equals both 2 and 3

Does the conclusion follow from the premises? Is the argument valid?
 
p1 All Greeks are geeks
p2 Joe is a Greek
p3 Not all geeks are Greeks

Which of the following conclusions are valid.
c1 Joe is a Greek geek
c2 Joe may or may not be geek.
 
steve_bank said:
p1 All Greeks are geeks
p2 Joe is a Greek
p3 Not all geeks are Greeks

Which of the following conclusions are valid.
c1 Joe is a Greek geek
c2 Joe may or may not be geek.
Click to expand...
C1 appears to follow from p1 and p2.
 
An axiom in classical logic.

If a = b and b = c then a = c.

A rock weighs 100kg. A log has the same weight as the rock. A boat weighs the same as the log. Therefore the boat weighs 100kg.

Logically why is this valid? What is the proof of the axiom?
 
Is it possible to be hypercritically hypothetical?
 
steve_bank said:
The science forum has the dumb question thread. This is for dumb logic. No need to srart a new thread for every idea. Lump it all together.

for example.

If a conclusion follows from a premise that is obviously absurd then the argument is structurally valid.

The Earth is flat and thin, so if I step off the edge I will possibly fall off and there is no air past the edge..
Click to expand...


I want to list, what I think, all possibilities.

There are assumptions, and there are conclusions that are obtained by logic.

The assumptions can be right, wrong, and incorrect. The logic can be correct and incorrect. Let me explain.

Correct logic is if the conclusions follow from assumptions. Otherwise the it is incorrect.
The assumptions can be self-consistent, claim to reflect reality (physical) world, but actually do not. This is the flat earth assumption (if it also claims that it is what actually is). Then this is wrong.
The right assumption is self consistent, and if it claims that it reflects reality, then it actually does.
The incorrect assumption is the one that is not self-consistent. "Suppose you have a sword, that can break any shield, and a shield that can stop any sword".

So, which of those is dumb logic? I argue it is the incorrect logic. The flat earth example does not belong to it - it is wrong assumption, correct logic.
 
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