The Argument Tool

I decided to put this up to help people. I’m not singling anybody out, or calling into question the validity of any particular argument. Rather, I thought this might be a helpful tool for users.

With this being said, I will attempt to provide an “easy to understand” reference guide, that users will be able to look at and determine for themselves whether an argument is valid or invalid.

Key Terms:
Statement – an assertion that something is or is not the case… I am a male… This triangle has three sides… You are a liar
Premise – statements that support the conclusion (statement).
Conclusion – the statement that the premise/s support.
Argument – a group of statements for which some provide support (premises) for another statement (conclusion).

I realize this may be a bit confusing from a technical standpoint, so if you have questions at anytime feel free to ask me directly.

Explanations are not arguments. In arguments we attempt to decipher whether something is or is not the case. Arguments have something to prove, explanations do not.
Example
1. Four people saw Jim steal the apple, obviously he did it. (argument)
2. Jim stole the apple because he was hungry. (explanation)

Deductive vs. Inductive
In a deductive argument one must accept the conclusion.
Inductive on the other hand, leaves room for acceptance of the conclusion… most likely, probably, most of the time…

Deductive:
Arguments can be either valid or invalid. If the premises logically support the conclusion it is valid. If the support is logically flawed it is invalid. Continuing on, if the premises do support the conclusion of a deductive argument the conclusion must be accepted.

Valid example.
All men are mortal.
Socrates is a man.
Therefore Socrates is mortal.

Invalid example.
All men are mammals.
All dogs are mammals.
Therefore all men are dogs.

Inductive:
If an inductive argument provides logical support for its conclusion it is said to be strong. If it fails to provide such support it is weak. Again, in an inductive argument we are looking for “probable” acceptance.

Strong example.
99% of men are mortal.
Socrates is a man.
Therefore Socrates is most likely mortal.

From this we observe the logic of the argument being made. Not worrying about whether the premises are actually true or not.

Example.
All men can fly.
Socrates is a man.
Therefore Socrates can fly.

Do note that this argument is deductively strong, but is not a sound argument. A sound argument would have true premises.

It is entirely possible for a deductive argument to have; false premises/ false conclusion, false premises/ true conclusion, and true premises/ true conclusion, and still be VALID. It is impossible for a deductive argument to have true premises/ false conclusion and still be valid.

A good inductive argument must also have true premises.

Example.
99% of men have three eyes.
Socrates is a man.
Therefore Socrates probably has three eyes.

This argument is inductively strong, being that its premises do support its conclusion, however it is not Cogent because the premises are indeed false. A cogent argument is an inductive argument with true premises.

A little repeat.

Deductive – valid or invalid
(Pretend the premises are true) if valid you must accept the conclusion, cannot have true premises and a false conclusion. If the premises actually are true it is good.
So that the flow goes like this Valid – Sound – Good.

Inductive – probable support
If premises provide probable support for the conclusion it is strong, otherwise it is weak. When the premises actually are true it is cogent. Valid – Strong – Cogent.

Valid conditional forms:
Affirming the antecedent:
If P then Q
P
Therefore Q

Denying the consequent:
If P then Q
Not Q
Therefore not P

Hypothetical Syllogism:
If P then Q
If Q then R
Therefore, if P then R

Disjunctive Syllogism:
Either P or Q
Not P
Therefore Q

cont'd

Invalid Conditional forms:
Affirming the consequent:
If P then Q
Q
Therefore P = INVALID

Denying the antecedent
If P then Q
Not P
Therefore not Q = INVALID

There is a lot more to it, but these are the basics… more to come so standby.

References:
The Power of Critical Thinking by Lewis Vaughn 3rd edition. 2010


feel free to move this thread where it belongs.


[edit on 7-8-2010 by monguzi]

That is a good start. Thanks for posting that.

The Socratic method still works.

Oh, many a girl friend would probably agree with the argument that all men are dogs.

The most important class I ever took in college was Logic 101. Why this isn't de rigour for every student (hell, even for high school)?

Well, I think we know why.

[edit on 7-8-2010 by jcrash]

Hi,
and thanks for your post. It's an interesting take on things, but it's too heavily reliant on definite logic, which is really just a convenient word that excludes the unknown in the real world, a bit like the three eyes premise.



[edit on 7-8-2010 by smurfy]

reply to post by jcrash

The most important class I ever took in college was Logic 101. Why this isn't de rigour for every student (hell, even for high school)? Well, I think we know why.

See George Carlin's thesis on this topic.

reply to post by Smack


nice vid... i liked that

Nice.

You might want to also include Toulmin argumentation

en.wikipedia.org...

Or equally, Goal Structured Notation (GSN) which as been developed for engineering but can be used for anything you turn it to.

Both are good tools for making a case that a particular thing is true.

[edit on 8-8-2010 by justwokeup]

If you really want to go off the deep end, look up Bertrand Russell (Analytic philosophy) or Kurt Gödel (Proof theory).