[Note: I have posted something very similar to this somewhere on MBTICentral before; this is a rewritten version.]
Suppose that a scientist is searching for theories which correspond to the facts, and by convention he labels such theories 'true.' One day a philosopher asks the scientist whether he has succeeded. Although the scientist has discovered some useful theories, each has its problems and he does not think any are true. But the scientist is then told by the philosopher that his theories must be true. He is then convinced by the philosopher that a theory is not true because it corresponds to the facts, but because it has instrumental value.
Does this mean that, if a fact is such that there's a land where no man can ever see, or interact with, then the theory based on that fact is untrue, simply because there can't be any instrumental value?
Disabused of the correspondence theory of truth, the scientist now adopts to the pragmatic theory of truth. Prior to his conversion, the scientist’s search for truth meant searching for theories which correspond to the facts, but now that is replaced by a search for theories with instrumental value.
But is this a sensible move by the scientist? The original aim of the scientist's search was the discovery of theories which correspond to the facts, and even though he may no longer label such theories 'true,' nothing else need change.
Suppose that the scientist lost his car keys and searched thoroughly to no avail. The philosopher then convinces him that the word 'key' really refers to a writing utensil, and therefore, advises that he search for that instead.
The philosopher is a wily bastard isn't he?
The scientist seems not to have much wit*: How certain are you that he's not a scientologist?
...
In any case --
The scientologist doesn't recognize that what the car needs remains the same even since the philosopher re-routed the scientologist's vocabulary.
What's the point of this part of the story? Even after having read, several times, the next section of your post, I fail to see what sense you're trying to make.
Words do not have real or essential meanings. For example, the word 'post' can refer to many different things--including a piece of wood set upright into the ground as a marker, a starting point at a racetrack, or an electronic message sent to a forum. But do these alternative interpretations constitute theories of post? Would it be sensible to argue about which theory of post is correct? The meaning a word is not a matter of discovering its real or essential meaning, but of negotiating a conventional use and interpretation. And although this principle is uncontroversial regarding words like 'key' and 'post,' it is often forgotten when discussing the word 'truth.'
And what a nasty problem this is.
So then, you mean to say that...
What the fuck are you saying? I'm searching with difficulty for cohesion.
You've misaligned an analogy.
*
The scient(olog)ist has theories based on facts that don't correspond with the results -- facts that would follow experimentation: other facts. So his theory must be based on the wrong facts. Or too few of them.
So he doesn't really have theories based on facts.
He has theories based on incomplete data, otherwise they would correspond to the world, which was, I remember, his original intention, with invariable accuracy and this entire discussion would never breathed its first breath.
On top of that, he trusts a philosopher, who, no doubt, works in construction, and dismisses the notion of his failure and, instead of correcting his theories so that they're not only proven right, and are based on facts.
This entire incident is highly akin to the problems struck out by euphemism.