The distinction between sense data and what you're calling logic/language I make merely by being aware of them as different. Logic/language is in my mind as a belief or hypothesis (and that is also a belief in my mind [that corresponds with a meaning I find myself with]) and then there's something I call sense data which doesn't fit the profile of the former. How was I able to know about each one and there difference is a good question. It's just as good of a question as asking how we learn the meaning of a word in the first place, or how we learn the difference between two pieces of knowledge. If you don't find these meanings/distinctions of 'sense data' vs. 'logic/language' then well, I certainly don't have a way of imputing it to your mind.

What may be relevant to ask you though is regarding your belief you have that sense data is "axiomatic" (I think that's what I've gathered). How do you account for logic/language and the whole metaphysical category of knowledge by sense data? As I've noted, that's been the well known problem for empiricists. If you don't like the distinction still I could simply give you certain meanings (the ones I happen to call metaphysical) and ask you to account for them.

There is other methods of gaining truth proposed other than empiricism.

Anyways, I've enjoyed the discussion as well, and I don't mind your long posts at all :) 

PREFACE:  FYI, this gets better as it goes; although all sections say important things, IMO the last three paragraps, especially second to last, are the best, if only because they are nice and concise.  Also, don't worry about abrasiveness; I'm being much worse. 

[edit:  PREFACE 2:  I missed something in my original response that may be key.  I'm editing now; it will appear at the bottom.]

A.
1. "Since we're discussing a method of truth... I wonder how you got belief X in the first place. It just ignores the whole issue of legitimately arriving at a belief which is fundamental to this."
'butbutbut any specific interpretation is just an assumption'
What I think you fail to grasp is the fact that the belief having no absolute rational foundation (i.e. does not defeat your skepticism) is IRRELEVANT to the fact that such a belief can EXIST.  So, no, that "issue" is not fundamental at all, but totally irrelevant to the point I am making.

2.  'butbutbut that sense data could actually mean anything if you interpret it differently'
Oh, so you are infact saying that the belief CANNOT exist.  You say it cannot exist because rational analysis will admit that that belief is not the only possible belief.  Well I'm sorry to have to break this to you but not all beliefs are 100% rational, and not all beliefs will capitulate when confronted with rational investigation.

"I can't ignore that and pretend someone can legitimately believe sensedataY must indicates cheese."  What do you mean by "legitimate"?  I think you are acting as if such a person having that belief would somehow have to prove you wrong about your skepticism in order to be possible.  In fact this is not true.  In fact, you are putting yourself in the position of PROVING to me that no person with such a belief can possibly exist, which doesn't seem very compatible with your skepticism to me.  Or, how does the nonrationality of a belief render it IMPOSSIBLE? 

If a person ABSOLUTELY BELIEVES that sensedataY means only Z, they will ONLY interpret sensedataY as Z, and the million other interpretations DO NOT EXIST to them.  If I understand you correctly you are trying to say that Belief Set A can't be contradicted by evidence because Belief Set B would not interpret that data as evidence against Belief Set A, but Belief Set B is not relevant whatsoever to the issue of Belief Set A being contradicted BY ITSELF (along with sense data that can only be interpreted one way by Belief Set A). 

I now think the bachelor comment is actually relevant when I actually just included it as a laugh.  Suppose I have ABSOLUTE CERTAINTY (nonrational but then I'm not a rational man) that Guy is a bachelor.  Suppose further that I have ABSOLUTE CERTAINTY that only married men have rings on their fingers and also that I can accurately detect said rings.  Now I witness a ring on Guy's finger.  ZOMG!  One of these certainties is incorrect.  If I choose to interpret the evidence in a way such that I can continue to believe that Guy is a bachelor, that is just as bad as if I decide that "bachelor" actually means "married man". 

"A. and B."
"I believe Z and also that A - Y are demonstrably false. ...Oh, but I'm not saying I know that."  There's your problem I think. 

Or, your 1, 2, 3 interpretations of "belief vs. knowledge" ignores 4. knowledge is provable/proven belief.  So we can prove, and thus know, things WITHIN our input/output data, but we can only BELIEVE that said data and knowledge is actually TRUE knowledge of a "really for real" universe.  (Or believe something else, or nothing.) 

I suspect that you are failing to differentiate what is true/provable/possible WITHIN a belief set vs. what is true/provable/possible for ALL belief sets.  Thus knowledge is differentiated from absolute knowledge, the latter of which is what you say cannot be derived from sense data (and I don't disagree).  Here you appear to be saying that regular knowledge is not possible either, but I disagree.

[edit:  "When I know to hit "Y" on the keyboard to make it show up on the screen... that's right, I don't believe I came to know that through sense data. Again, there are other methods of truth proposed."

[WAIT, WHAT?  How did you not sense it?  Even if God drilled a hole in your head and delivered the information via a teaspoon of pixie dust ... you still received sensory data of pressing the key and seeing the Y.  Also, by "don't believe" do you mean disbelieve, or just lack of positive belief?

[Also, I believe that this does not actually address the point you were responding to, which is partly about consistency of the perceived world with perceived actions, not method of reception of perception.]

Oh man, I just realized. Strap yourself in and prepare to be blown away because here comes a SHORT VERSION:

"I can't ignore that and pretend someone can legitimately believe sensedataY must indicates cheese."

But can they ILLEGITIMATELY believe it?? Stupid belief sets are not excluded from "ANY".

lets have some fun:

I Belive that the Universe was created by a Pink Bunny called FluFlu, who is also a deity who i believe in, FluFlu requires only my belief in him to be happy with me and will reward my sould with eternal life in Pinksy World (Heaven, But Pink!)

Prove that the above hypothetical belief is right or wrong or at least more right or wrong than any other religions beliefs.

im an Atheist, but i dont claim to be able to disprove it, i cannot prove FluFlu does not exist, but i know enough about Science to think its unlikely that he does.

why is it only the Christians that turn to atheism and usually not other believers of different faiths.

My edit could be a little more clear but I have to go to work. Hopefully you'll get my intent on the last part. 
[edit:  I'm gonna let it stand.]

What in science makes you doubt the existance of FluFlu?  Scientific understanding wouldn't preclude a creator it could simply explain how what the creator created actually works.  In one paragraph you acknowledge that you cannot prove or disprove something like God and then in the next paragraph claim scientific knowledge as at least a partial basis of your disbeleif...so what scientific knowledge makes you think it is unlikely but is unable to disprove it?

End of the day these people still want to celebrate christmas and easter both of which are Christian values.  If one is a true atheism then they should not be having time off at christmas, easter or any other religious holiday.

Nobody should really respond to a post like this.  But I'm bored.

I'm an atheist and I love parties, celebration, and the goodwill associated with these holidays.  I enjoy giving and recieving gifts, and I love robin's eggs.

Most of the things that I love (and things that you likely love, too) about these holidays having nothing to do with Christianity at all.  For instance, gift-giving, feasting, Christmas trees, Easter eggs, the Easter bunny, and even the name "Easter" all have their origins in non-Christian traditions.

So much so, that there have been (and are) Christian groups out there that have refused to celebrate either Christmas or Easter because they feel that both are, essentially, pagan.

So, "end of the day," maybe it's Christians who should be working through those holidays, and give the time off for us atheists.  After all, if Christians get to spend eternity in Heaven while we're baking in Hell, we might as well have some fun on earth.

By the same token if one is a true Christian they should probably go to church most weeks..but we know how that plays out in the real world. 

Thinking more about this thread I wanted to add a bit to my thoughts from before:

Interestingly, and at the risk of offending (although I don't intend it in a harsh way to either side) I think agnostics are the only people who are being completely intellectually honest.  What I mean is that you are either basing your beliefs on logic or simply on faith.  If you base it on faith then nothing intellectual (in the academic and logical sense, not the intelligence sense) enters into it..its just faith and is imo the only valid reason to make up ones mind either way.  On the other hand those who claim to believe or disbelieve in religion based on logic are imo being intellectually dishonest because it is quite obvious that matter cannot be proven.

Trying to say that you come by your beliefs by way of anything but faith is the sign that the person is either lying to other people or themselves (usually this option), else they should make their logically based proof known to the world (we'd love to hear it). Logic and reason that fails to result in a proof can get you started in any direction you want to go, it's actually arriving at a conclusion by logic and reason that allows you to place that logic and reason in support of your belief and claim it as a logical or reasonable belief...anything less is using your faith in your own logic and reason up to that point to bridge the gap to a conclusion. But logic and reason are only useful in their pure form.

To repeat this again.  In order for a belief to be logical it must result from an unambiguously deterministic set of logical steps.  In order for a belief to be reasonable, it must result from an unambiguously deterministic set of reasoned assertions.  Note that because these are logical steps and reasoned assertions the issue of perception being valid is assumed, but this is of no consequence since those who this is addressed to must necessarily accept that premise as part of their having made the assertion that I object to.  If your belief is truly logical or truly reasonable then you can say that logic and/or reason supports it.

So whether you are an atheist or a theist your view still comes from faith and not logic or reason because no such logic or reason exists to support either position.  This goes to my last post quite strongly, and that is that many atheists (but not all) have claimed all of the visible world and its lack of a readily apparent divine presence as their proof...but what claim do they have to that other than societies labeling of energy and forces that we still can't explain the origins of?  Origin is what the theistic and atheistic belief is centered around and until you reach proof on this with logic and reason you're intellectually dishonest to claim logic and reason as being in support of your beliefs on origin.  Short of that it is your incomplete logic and your incomplete reasoning that are actually in support of your position for whatever they are worth, and nothing more.  Let me illustrate...

Imagine if you're knocked out and when you come to you can't see anything.  1) Are blind or are the lights just out?  How do you know?

There are two voices in the room with you and they both report that they are experiencing the same thing that you are but they each believe oppositely.  One of them tells you that the source of the problem is a lack of light in the room and the other believes you are all blind. 2) Based on their commentary are you blind or are the lights just out?  How do you know?

You might think it was odd that they (your captors) should blind all of you, and there are certainly numerous motives that you could project onto your captors to decipher what they would, could, might, or might not do.  But you're already making the assumption that their minds work in a similar fashion to your own even though you would never kidnap someone.  3) Based on past experience are you blind or are the lights just out?  How do you know?

Now, lets say that someone finds what feels like an old flashlight in the room.  And they move the switch back and forth from position to position in an attempt to make it turn on, but still you can't see anything. Now the person who says you're all blind is saying "see!" and the person who says its just a lack of light says "the batteries are probably just dead!".  4) Based on this new information are you blind or are the lights just out?  How do you know?

It's perfectly legitimate to say you believe one way or another...in matters where a course of action is required it is a survival mechanism to make a choice, even if the choice could be wrong.  But it's another thing entirely to insist, despite lacking any evidence, that your position is true based on logic and reason.  It's not..it's just based on faith.