How do we know, that what we know, is what we REALLY know?

When I was a Junior in High school I took a very interesting and intellectually stimulating class called Humanities. During our first semester we were studying Philosophy. All of the students were put into groups and given questions that Philosophers have been trying to answer for centuries. The question that I received was “What is Real?” But the question that interested me the most was one that another classmate received and I thought I would ask you…

How do we know, that what we know, is what we Really know?

My classmate argued that we know what we do based upon what we are able to touch, see, taste etc. based upon our senses, but can’t our senses be fooled or incorrect at times?
(obviously they can)

Other people in her group argued that we know what we do based upon other people’s findings and theories, pictures that we see in history books, newspapers or on t.v. or written accounts from scientists and great minds from the past; but we
weren’t there, experiencing first hand…

I am now a Freshman in College and to this day I still ponder this question, I have read through many “silly” questions that you have sarcastically but very intelligently responded to and thoroghly answered - it would be intersting to hear what your input on this subject might be.

Sincerly and Curiously Yours,

This may not have a factual answer as required by the forum, might be better in Great Debates since it’s an open philosophical question.

We did this one in Philosophy 101 in college. Presumably there is a reality out there but all you can know is your perceptions. Ask Neo what was reality before he took the pill-theoretically everything you experience as reality could be an illusion. Some scientists even say our experience of the passing of time is illusory.

This is one of those things you could write volumes on but that’s it in a nutshell.

Have you ever looked at your hands? I mean, have you ever REALLY looked at your hands?

As Neo and the Matrix replace Plato and his cave, so goes humanity.

Descartes’ claim:

Wasn’t his conclusion: We can only be sure that we “think”, everything else is in doubt?

We’re all windowless monads. Or at least I am, until I take the leap of faith required to accept that my senses are telling me something about something that exists outside of myself. Then I can start to develop all sorts of convoluted theories about exactly what that something is, as well as the other somethings that, like myself, seem to inhabit it.

micco, I read that link but it’s lacking, Plato should have thrown in some guns and lots of sex. Even the people seeing shadows of sex would have been ok. A long chariot chase down the streets of Athens would have also helped.

Yeah really, I mean I respect Plato, but damn the Matrix was one sexy (I use that term very loosely) movie.

This is the subject matter of epistemology. Study it, know it, love it.

Most people would rather just pontificate over a glass of chardonnay.

This is more of a Great Debate than a General Question with a factual answer.

Off to Great Debates.

DrMatrix - GQ Moderator

The Long Road, you crack me up. :slight_smile:

To the OP: this is one of the perennial problems of philosophy, more specifically epistemology (as KP noted). There are no fully convincing and generally accepted answers. Some historical positions:

Spinoza (in his treatise on the improvement of the mind, IIRC) thought you would recognize real knowledge somehow when you encountered it, you just had to think clearly about it. Descartes’ concept of clear and distinct ideas was similar.

Hume paid attention to this problem in his Treatise. IIRC he admitted getting in a very confused state of mind if he thought to deeply about it, then found that when he got out to the pub all his confusion dissipated. (yes, it really says so, albeit not in these exact words)

Descartes’ Deceiver is a god who feeds us nonsense called “logic”, “mathematics” and “reality”.

We cannot know that this isn’t the case (or indeed, since logic is one of the pieces of nonsense, that it is AND is not the case simultaneously). Nor can we even present any evidence one way or the other because no piece of evidence distinguishes real-world from DD-world.

All we can do is set the needle of our belief-o-meter strongly towards real-world and away from DD-world, without ever allowing certainty.

I would tend to combine these two.

Point 1:

If we presume that our senses can not be trusted at all, then there is no rational way to observe reality. The concept of reality itself becomes arbitrary and objectively meaningless. Technically one could postulate some sort of existential spiritual reality beyond the physical, but to my mind one particular version of such an unverifiable “reality” would seem to have extreme difficulty establishing more rational validity than any other dream or imagined construct… While most people will gladly admit their senses can be deceived or that observations can be misinterpreted (perhaps not necessarily incorrect per se), at least when one uses one’s physical senses there is some potential for objective verification by other minds. Which brings us to…

Point 2:

If we presume our senses can be trusted to some degree, generally this leads us to reject solipsism. If we observe that we are human and there are other humans around us, the most likely explanation is that the other humans are like us in their capability of sensory interpretation and thought. And as such, it is not an unreasonable leap to accept that we exist in some sort of reality collectively, and that our combined observations of that reality can establish a collective objectivity of sorts.

Of course this is not to say that the majority is always right–only that we can, for practical purposes, agree by convention that (to quote James Burke), “Reality is what we say it is.”

Granted, there are some fairly significant assumptions being made, but none of them seems to be so terribly bad as to suggest that you should pull your plug, rebel against the machines, and…


SYSTEM ERROR 32. Abort, retry, fail?


You can get your Macroscope

There is no “really” knowing something. There’s just knowing. There isn’t any underlying truth we’ve got to uncover; the moment we find it, we know it. Sure, we were wrong before, but now we know better.


Seriously, though. There is nothing gained by intensifying the verb “to know”. It isn’t as if people ask, “Do you REALLY know that?” and the response is, “Oh, I was just talking about everyday knowledge.” Knowledge is knowledge: the ability to demonstrate belief. We know because of two things:

  1. We agree on a method of demonstration; (for the philosophically inclined: the pull towards foundationalism)
  2. We agree on a common core of understanding. (for the philosophically inclined: the pull towards coherentism)

Knowledge is then revealed by the demonstration of what is said to be known referencing existing understanding (or in the case of more complicated assessments, existing understanding and previously revealed knowledge). More can be known than propositions about the world; tasks can also be known, and there are ways to demonstrate one knows them (usually by performing the task). Knowledge is not strictly a matter of logic—though that might be one way we demonstrate it. Knowledge is not strictly the consequence of demonstration—for we can demonstrate a grasp of the tools used to demonstrate in various contexts (think on the difference of “knowing a theorem” of arithmetic by demonstrating it through it versus what you’d show someone to demonstrate you “know arithmetic” and the distinction I draw might become clearer).

We cannot come to understand the activities of perception until we are taught the word “perception” and the various ways humans look at it already… by then it is too late[sup]†[/sup]. At that point the only thing that dispels one type of demonstration is a “better” demonstration, but we are never without knowledge. The best that can be said is that we attempt to disregard our naive tendencies to assume what we already know and regard the world through eyes that don’t see objects and colors but simply raw sensation. The utility of this method has been thought on by phenomenologists, most famously Husserl, Heidegger, Merleau-Ponty, and Sartre. The conclusions they came to from this method vastly differed from Descartes who purportedly undertook the same, or a similar, method (even though Husserl was in many ways inspired by Descartes). What this indicates—I don’t feel like speculating on here (my opinions on Descartes can be found in at least two threads here in GD).

Importantly, there are some things that we might come to say we know but that are not strictly knowledge in the sense I have described above. These are the sorts of things people often reference when they intend to intensify the verb “to know”. For instance, how does one really know other people exist, or how does one really know whether this is a hand (that is, my hand). These sorts of brain-smashers are best handled with the above demarcation of knowledge. We cannot say we know some things because of criteria (2) of knowledge: the common core of understanding. The elements of (2) cannot be known; they are used to show what we know (I do not demonstrate that I have a hand when I draw; I demonstrate that I know how to draw with my hand).
†[sub]If you ever see me irritated with people who insist on only knowing things through perception, this is why. I find the position to be completely untenable. Hume’s exhaustive view of the primacy of perception remains, I feel, completely unchallenged. Either his path was the proper path, or his assumptions were wrong. I believe the latter, and require more of knowledge than sensation, which is really quite pitiful in its powers. For the artistically inclined, impressionism offers, I think, a fine visual aid for understanding why sensation alone (in this case, vision), is woefully inadequte to account for any knowledge whatsoever.[/sub]

OK. So help me with this erislover. How does one make the jump between sensation and reality. That question is not meant in any snotty manner.

My take would be that everything I know is through my senses. I’m no solipsist but I can’t be sure that I’m sensing accurately. I think there is an objective reality out there but I don’t know (oops) that it jibes perfectly with any other’s view. If it jibes with most othere folk’s version we agree that it’s all real.

By the way, I never took Phil 101 so any basic help is appreciated.

And by the way, welcome to the boards AliceNChains.

(shrugging) We don’t. Try not to let it get to you.

Hmmm. When I studied logic in my Computer Science classes, the key words were: AND, OR, NOT, NAND, NOR.

Now, let’s look at the underlined words in your statement:

We can not know that this isn’t the case (or indeed, since logic is one of the pieces of nonsense, that it is AND is not the case simultaneously). Nor can we even present any evidence one way or the other because no piece of evidence distinguishes real-world from DD-world.

Sorry for the nit-pick. :wink:

Ah, Wake up call, there is only and shall only ever be NAND[sup]*[/sup]! :smiley:

*[sub]for those not in the know, all logic operations can be done by the application of NAND in various configurations. For example, NOT is A NAND A. AND is NOT NAND (and we’ve already shown NOT). Etc…[/sub]