What is knowledge?

Could be a fun question. Just to start, it certainly seems like "2 + 2 = 4" would be true even if nobody had knowledge of that fact. So truth and knowledge can't be the same thing. But I think that truth is a necessary condition for knowledge--that is, you can't know that "2 + 2 = 4" if it isn't true that 2 + 2 = 4.

If truth is a necessary condition for knowledge, is knowledge impossible for things with no agreed upon truth? In other words, can I know blue is the best color, while you know red is?

At first I thought knowledge is facts understood. Since justlurking suggested that truth is a necessary condition for knowledge, I thought the facts must based on truth. But, then I realized there is a fine line between the necessity of truth to be part of knowledge. If a primitive tribe believes that a horrible demon god lives beyond the hill, is that knowledge based upon fact when what they are referring to is hermit with a severe case if Giantism and a bad temper? In the case of the primitive tribe, then the knowledge melts down to perceived danger which, for them, is the truth.

Perhaps knowledge is based upon perception, and agreed upon identification. In the present day situation where the discovery of a new bacteria with building blocks made of arsenic was announced, those results immediately became widespread "knowledge".

If knowledge is based upon truth, then there is a great deal of which we are ignorant. Therefore, ignorance is not bliss. By the same token knowledge is not bliss. Knowing with a scientific certainty beyond a doubt that a world busting meteor is on a direct path for earth would be an example of that.

What I would like to know if it is true that knowledge is power.

I think it's interesting that you make a distinction between types of knowledge - some is useful, but some (like your meteor example) is not. I agree with you here, and have an idea as to what the difference is, do you? I guess the real question here is, what is the PURPOSE of knowledge?

Knowledge is anything you know, and largely unrelated to truth.

I know a variety of of things about emotional states all the time, but don't know if they're true (i.e., I know my wife is pissed at me when she does X; sometimes, though, she does X because she's pissed about something else).

It matters a whole lot since everything I do is based on what I know - even though what I know might not be true...

I'm so sorry to hear about your house being broken into. I have heard that some burglars hit the same house again in 6 or 8 weeks thinking the occupant will have used insurance to replace all the electronics with shiny new ones.

I think I'd have a hard time relaxing enough to sleep in my house if it were broken into. So sorry you must deal with this type of thing.

Ignorance is bliss, for those who would manipulate you and use you.

It is like wearing a nappy(diaper). At first, it is warm, snug and secure. In the end, it is very smelly, uncomfortable and dangerous.

1. For centuries the Ptolemiac model of the solor system ruled. It more accurately predicted the appearance of the planets than the initial heliocentric models. Clearly, there was truth in the predictions made by this model, but it was not based on genuine knowledge.
2. Ignorance frequently is bliss. Knowledge can bring very painful realities to whole systems of thought and cultural mores. People become accustomed to these things and this pseudo-knowledge can bring about a sense of security. Just because something brings about happiness doesn't make it a good thing.
3. In regards to, "if ignorance is bliss, tis folly to be wise," Galilieo concluded his appointment with a whispered, "she moves," and he certainly had more insight, truth and knowledge than those who sought to censure him...but that didn't really help him get out of his apartment for the last years of his life. Ironically, there are faith based systems today, who use Galileo as an example to give up logic and reason and cling to faith, as an example of enduring in the face of adversity.
4. I am a Christian, but personally, I believe Christ tried to overthrow the notion of clinging to bad or poorly thought traditions. Unfortunately, many times religion is guilty of providing an excuse for some to maintain their bad ideas.

@ eNeMeE - that's interesting, so knowledge is relative, but truth is universal?

@ Tex - Thanks for your concern. The first guy was caught and convicted, this one is probably unrelated - we don't live in a great neighborhood, and the economy sucks. I'm less worried than my roommates, I think it's mostly petty crime, but still...

@ MacTurk - so would you say ignorance is always inferior to knowing? What about in the meteor example raised above?

@ Mike - 1. You seem to be saying the opposite of enemee, that truth is a bit more relative (or at least there are degrees of it), but that knowledge must come from capital T Truth.
2 - interesting distinction, it can be bliss, but that's not necessarily good. I agree completely, but are there conditions where ignorance is both blissful AND good?
3 - Not sure I fully understand the point here. Was it folly for Galileo? Or are you saying it wasn't in hindsight, even if it might have seemed that it was at the time?
4 - There's always a place for religion in a discussion of this sort, especially for an atheist like me, but I'm not sure I want to wade into that nest of cobras just yet.

1. Yes, truth is relative. Or more to the point, a theory not based on reality can be useful if it provides valid information that improves life. In my initial example, if more and more extensive "props" allow form accurate prediction using the ptolemiac model, which in turns allows for a greater understanding of time and navigation, that is a great thing. Even though the base upon which that knowledge is built is false. I would point out that by the same token, ignorance can beget ignorance while making use of some knowledge...again, with an understanding of astronomy charlatans can use astrology. Claiming to predict the future based on an ability to predict the position of the planets or stars.
2. I'd harken back to the meteor example. If knowledge of impending doom only creates terror and fear and nothing can be done to change that doom...then ignorance is bliss. But, you have to admit, that is pretty damned conditional. Whose to say what can change with a bit of knowledge. "Forewarned is fore armed."
3. I'd say again, we are dealing with a matter of conditions or points of view. Galileo capitualating to the inquisition saved his life, but did not stop the knowledge from being spread. Arguably, Galileos knowledge was folly in his expressing it, as it allowed religious zealots to hold him prisoner...at the same time, it should be considered that Galileo also could have fled...and that his expressing this knowledge and insuring it got out was for the betterment of mankind. There is a big part of me that believes Galileo's expressing his knowledge was folly for him but was not folly for the rest of mankind. He was an unwitting and unrecognized martyr...and obviously despite the fact it did him injury a man who felt it important to stay tied to his society(in this case through his church).
4. I agree. I mentioned it here, only because I did not want this to turn into a thread that was simply a flame war. I have/had no desire to make it about bashing the religious or the non-religious.

@Mike
1. I think we agree here, I would just use different words. My definition of "truth" is sort of synonymous with reality, but I agree that predictive power is key - more on that later.
2. Agreed 100%. This is sort of what I wanted to write about - maybe it's self evident.
3. I see what you're saying now. It's an interesting distinction between self and other when it comes to ignorance - certainly the effect of knowledge vs ignorance (positive or negative) can disproportionally affect certain individuals or communities.

"@ eNeMeE - that's interesting, so knowledge is relative, but truth is universal?"

Knowledge is things known so yes, it is relative. I know Santa doesn't exist, but many little kids know the opposite. The truth of "whether or not Santa exists" clearly can't be both (semantic quibbles about the idea of Santa aside), and would seem by all accounts to make the knowledge of the little kids false - much the same way that many people know AGW, or evolution, or an ancient Earth are false.

There's some muddling and bleeding of terms, such as belief, understanding, comprehension, etc. but that's always going to happen when using general language to identify something - it just isn't precise enough....