How do you know when something is true?

(Max, you're not allowed to play yet.)

It is revealed by a trusted source.

I see my wife across the room, my eyes have become trusted sources, I know she is in fact there.

OK, that's one suggestion. Let's get some others before evaluating.

It is the result of defined actions on defined objects (ie, based on the definitions of 2 and 4 and the definition of the addition operator, 2 + 2 = 4).

Though I don't think this is a very good answer (to what is an interesting question to ponder).

Since the time of Descartes, it's been the principal question of philosophy. Don't let that scare you (or anyone else) from answering.

Are you asking me personally, or is the "you" meant to mean every human? If the latter, then Jimbo gives the best answer possible.

FJ

This is a free-form question. Since I'm not grading this, any answer -- even to a different question than I intended -- is acceptable and might even shed some light on the discussion.

I don't know. Jimbo's first answer is pretty good - but only if that souce is knows the truth - not just becuase one trusts them (which I guess you could argue that a trusted source actually knows the truth but then it seems circular).

I'm not sure the example he gives is a good one though - I might look across a room and see Tiger Woods only to later find out that it was merely a paper cutout on an ad display of Tiger Woods at which I was looking.

We're not evaluating yet. But when we do, your objection is the first one I'm going to raise.

Yes, but the question is tricky. It asks how I KNOW something is TRUE. The 2 words SHOULD be related to each other, but since the question is ultimately subjective, someone could KNOW something to be TRUE, though they are in error. I suppose it depends on how you read the question.

Jimbo's answer is the best possible without these flushed out, because if you trust a source, then you will believe what you hear and say "I know this is true because I heard it here." Though, you may be wrong.

FJ

Let me restate the question because I think the way I put it is taking us down blind alleys a little too quickly, and I see FJ is picking up on it.

When I say I know something, what do I mean?

I hate quick fire philosophy conversations on message boards, but I am extroverted tonight so I will throw this out without thinking about how it should be phrased... I see 3 possibilities.

1. You mind matches up with your experience of reality;
2. your experience of reality has impacted your mind and the mind conforms;
3. or what you are told about reality from a trusted source.

FJ

Lets see when you say " I know something" I would say it means you got a secret! so out with it we want to know...

Just joking My answer would be if you say you know something then to me it would mean you possess a certain knowledge on a particular subject that you surmise to be irrefutable?

When you have proven that it is not false.

But is that really true?

IOW, is this correct:

"Something" is either true of false,
This "something" is not false,
Therefore, it must be true.

That's a valid form of deductive logic (a dichotomy, to be precise), but it still leaves open the question of how you know you've proven something false.

This is the law of the excluded middle. It is true in classical mathematics, but there is branch of mathematics called "constructive mathematics" where this law is does not hold.

We can not prove truth...

Truth can not be proven in this life; therefore, It is known by faith, because we do not have conclusive evidence to prove God, Who Is Truth and the Source of all truths known by man.

God is the beginning of all truths known by man since He Is Truth. In order to prove all truths known by man to be true, we'd have to prove the premise or source of all truths, known by man, to be true; which we can't, because the source of all manifested truth known by man is God.

Even scientists must have faith in their discovery of certain "proven" truths within nature or the universe; obviously, because they can't prove the beginning Source of all these truths.

My 'answer' was purely rhetorical. The world 'false' could have been substituted for 'true' in Obi's originally result and my 'proof' would have been just as unsatisfactory. It is circuitous.

PDUBYA is on to something, but can we always assume that truth orginates with God? For example, we know that water freezes at 32 degrees F. We know that it is true. We are not asking who is the originator of this truth, we only observe that it is true.

Actually, we only know that water HAS frozen at 32 degrees for the time that we have noticed. Beyond that, you open up another can of worms. How do you know that the water you put in your freeze right now will continue to behave in the way it has in the past?

EDIT - I mean... You COULD 'know' that your water will freeze. But how?

FJ

oh yeah----and what if that is a "clone" of jimbo's wife---or a perfect twin?

or like some movies have it---someone experienced in dressing and looking like someone else....