## Truth tables in debate

This is the main board for discussing philosophy - formal, informal and in between.

### Truth tables in debate

I’m intentionally trying to earn a sticky on ILP!

So something is either true or false right?

Not quite. We have something in argument called the truth table. It goes like this:

True / True
True / False
False / True
False / False

The advantage of truth tables is that they deal with double negatives.

What the chart above in plain English is that:

It’s true that it’s true
It’s true that it’s false
It’s false that it’s true
It’s false that it’s false.

The two that equal each other as being true are it’s true that it’s true and it’s false that it’s false.

In debates, ambiguity occurs with the middle two of the truth table: it’s true that it’s false and it’s false that it’s true both solve as “false”, and also as a paradox, to make debate subjects unnecessarily confusing.

It helps to point out which of the four truth tables is being utilized to clarify where parties are at with respect to presenting their subjects of debate.

To have a grid that’s more than true : false and the two gridded truth tables becomes redundant. It’s only important to this regard to discuss what is commonly known as the truth table which allows for double negatives and more.
Ecmandu
ILP Legend

Posts: 9290
Joined: Thu Dec 11, 2014 1:22 am

### Re: Truth tables in debate

People usually don't use true/false logic. They use multi-state logic ... true, false, unknown, indeterminate, probably true, probably false ...

That sort of stuff.
phyllo
ILP Legend

Posts: 11514
Joined: Thu Dec 16, 2010 1:41 am

### Re: Truth tables in debate

phyllo wrote:People usually don't use true/false logic. They use multi-state logic ... true, false, unknown, indeterminate, probably true, probably false ...

That sort of stuff.

The latter all mean: not necessarily true and/or false.

This solves as a contradiction to the reason for stating it in the first place, unless it has a qualifier as to WHY!!, which puts it back on the truth table.
Ecmandu
ILP Legend

Posts: 9290
Joined: Thu Dec 11, 2014 1:22 am

### Re: Truth tables in debate

Empirical truth is on a spectrum so it cannot be limited to just four variables

Those four varaiables may be false anyway where such truth is concerned because of the problem of induction
For example something may be regarded as true because of evidence but subsequent evidence may falsify this

Only where proof is concerned with regard to logic can one deal in absolutes

So for example the statement one and one is two is absolutely true because it can never be falsified
Because mathematics is a branch of logic and logic uses proof to determine the truth of propositions
A MIND IS LIKE A PARACHUTE : IT DOES NOT WORK UNLESS IT IS OPEN
surreptitious75
Philosopher

Posts: 1213
Joined: Sun Aug 27, 2017 5:48 pm

### Re: Truth tables in debate

Empirical truth is on a spectrum so it cannot be limited to just four variables

That's not true. The truth value of a representation can be binary classified and that's usually enough. But not always, of course. Sometimes, you want to know the degree of falsity i.e. how false a belief is. If you're 6'3'' and I think you're 6'4'' then I am wrong but not as wrong as I would've been if I thought you're 5'8''. And if it was necessary to know how wrong I am, then simply saying I am wrong, although true, wouldn't have been enough.

s75 wrote:So for example the statement one and one is two is absolutely true because it can never be falsified.

You can look at it another way.

The statement "1 + 1 = 2" is a statement about language. What it means is "Everything that can be represented by expression 1 + 1 can also be represented by number 2." This is either true or false and it depends on the rules of the language of our interest. Since the rules of any language can be observed, e.g. in the way it is being used in practice, the statement is not so different from the so-called empirical statements. Even if it's a language you invented just a few moments ago, you must recall the rules you've invented; the choice is certainly not an arbitrary one. In other words, the statement can be falsified.

Every statement that has truth value (which is to say, every statement that is a representation of some portion of reality) is testable and therefore falsifiable (since tests either verify or falsify a claim.)

Magnus Anderson
Philosopher

Posts: 3967
Joined: Mon Mar 17, 2014 7:26 pm

### Re: Truth tables in debate

Ec, baby. That's not how you read those truth tables. That's the chart for two terms to which a logical operator will be applied. You use this chart to account for all truth value (T or F) combinations of p and q and then you add a column for the expression that you are using these two terms in, to find out what happens in each case. It's got nothing to do with a "double negative" per se.

You can make a truth table with double negative truth values, but I have no idea why you'd want to that.

Your "plain english" translations are probably worth copywrighting, as they are yours alone, so far as I know.

Faust
Unrequited Lover of Wisdom

Posts: 16897
Joined: Sat May 21, 2005 6:47 pm

### Re: Truth tables in debate

Faust wrote:Ec, baby. That's not how you read those truth tables. That's the chart for two terms to which a logical operator will be applied. You use this chart to account for all truth value (T or F) combinations of p and q and then you add a column for the expression that you are using these two terms in, to find out what happens in each case. It's got nothing to do with a "double negative" per se.

You can make a truth table with double negative truth values, but I have no idea why you'd want to that.

Your "plain english" translations are probably worth copywrighting, as they are yours alone, so far as I know.

That makes no sense. Truth tables really exist, they are used to deconstruct paradoxes.

It makes no sense to say “true or true” “false or false”
But that’s exactly what a truth table is!! T/t, t/f, f/t, f/f. The whole point of a truth table would be meaningless if they all just used the “or” operator

Lots of natural language problems use double negatives. It’s true that it’s true solves as identity.

It’s false that it’s false solves as “true”.
Ecmandu
ILP Legend

Posts: 9290
Joined: Thu Dec 11, 2014 1:22 am

### Re: Truth tables in debate

"It's false that it's false" is "solved" by "replacement." To prove this using truth tables is fun only if you're drunk.

Replacement rules are very commonsense rules that are only called rules at all for the sake of having complete rules.

Faust
Unrequited Lover of Wisdom

Posts: 16897
Joined: Sat May 21, 2005 6:47 pm

### Re: Truth tables in debate

Faust wrote:"It's false that it's false" is "solved" by "replacement." To prove this using truth tables is fun only if you're drunk.

Replacement rules are very commonsense rules that are only called rules at all for the sake of having complete rules.

I looked it up. You are correct by the books. I’m going to use my ideosyncratic representation of truth tables for my own purposes.

To me, the regress (which can’t go any further than 2 variables without being redundant) is very useful. Regress is very useful in argument. You can’t get regress with t or f.
Ecmandu
ILP Legend

Posts: 9290
Joined: Thu Dec 11, 2014 1:22 am

### Re: Truth tables in debate

Regress for success.

If only there were a market for philosophy t-shirts.

Faust
Unrequited Lover of Wisdom

Posts: 16897
Joined: Sat May 21, 2005 6:47 pm