There are two kinds of "false doctrine".  Don’t confuse them:

1)    Statements or teachings that are false.
2)    Statements or teachings that are not known to be true.

Example: I take a coin, and put it in a sealed box.  I shake the box vigorously and then place it on the table without opening it.  I assert that (inside the box) I know that the coin is facing heads up.

That’s "false doctrine"—I don’t *know* that the coin is heads; that’s just speculation on my part without any direct evidence that it is true.

Okay, then, since teaching that the coin is heads is ‘false doctrine’, that means the coin must be tails, right?

No, making a conclusive statement that the coin is tails would *also* be false doctrine, as there is no more evidence that the coin is tails than it is heads.  That’s just as speculative as my original statement--the coin may be heads or tails, we don’t know.  My original statement, in fact, may very well have been correct, but since I don’t know for sure, making statements to the effect that I DO know for sure—that the fact is certain rather than uncertain—I’m creating ‘false doctrine’.

Okay, wait, that implies that some “false doctrine” may actually be true.  Well, yes, that exactly what it means.

“False doctrine” can include statements about truth that *might* be false (but might still be true), just as much as statements that are inarguably false.   Opponents of “false doctrine” can get themselves in trouble by assuming that the opposite of the “false doctrine” therefore is the “true doctrine”, when they don’t actually know any more than the original teacher did about what’s really true.

Example:  “There is no communication allowed between the resurrected spirits in the terrestrial kingdom and the celestial kingdom.  Once you’re in a kingdom, your only contact is among people of the same kingdom.  If you have family members in a different degree of glory…sorry!  Say goodbye to them now, you're going to be on your own.”

If I made that statement in sacrament meeting, I could correctly be said to be teaching false doctrine, since I’m making an authoritative statement about something where there is no direct evidence and is not known to be true.  Does that mean there *is* communication between the kingdoms?  No, there’s no direct evidence to make that conclusion, either.  Making the opposite statement would also be ‘false doctrine’ since that’s also not known to be true.  Who knows what the true relationship between people in different degrees of glory is? 

A more pertinent example:  “Exalted spirits will be made ‘white’ in the resurrection, regardless of their original skin color.”

Statements to this effect are rightly complained about—this is speculation, often hurtful and insensitive speculation at that.  It’s “false doctrine” because there’s no evidence that it is true.

Do we know, though, that resurrected bodies will, in fact, include racial characteristics, including skin color?  No, there’s no evidence that anyone can point to that shows that is any more true than the opposite.  The scriptures attest that the resurrection will bring bodies in “perfect” form, but what does that mean?  Will height, and body weight be maintained?  Who knows?

Telling someone who is overweight that “don’t worry, you’ll be skinny in the resurrection” may be just as hurtful to someone who is accepting of and has a positive self-image towards how they look now.   It something that shouldn’t be said for reasons of tact and sensitivity, and because it’s false and speculative doctrine…but which still might very well be true.  It would be just as incorrect to say that body weight WILL be persisted in the resurrection, because just as with race there’s no direct evidence that that would be the case.

Example #3:  “A person’s race, birth country, and birth family’s socioeconomic status is determined by how righteous and valiant that person was in the pre-existence.”

Yup, more “false doctrine”.  Other than the war in heaven, here’s everything we know about the pre-existence:

1.  
2.  
3.  

Do we know that the pre-existence had NO influence on a person’s status in mortality, then?  (Review the above list again…)

There’s no question that spirits born in mortality have a vast range of birth circumstances in terms of race, poverty and access to the gospel.  There are, in effect, two possibilities how God assigns spirit children to families around the world.

1. It’s random.
2. It’s not random.

If you lean towards (2), then that brings up the next question: if it is *not* random then how is it determined?  Was a child born into a wealthy, active LDS family more righteous than someone born into a family in a poor third-world country, with no missionary presence?  Or maybe they were less righteous, so they needed more of a ‘leg up’ to reach their celestial potential.  No one knows...so statements to either effect are fundamentally questionable.

Statements about the pre-existence—and I mean ALL statements about the pre-existence—are automatically suspect, given the lack of direct evidence from the scriptures.  That includes statements about race being determined by actions in the pre-existence.  It also includes statements that race is NOT determined by actions in the pre-existence.  (If it was, how would we know?)

Part of gaining wisdom is recognizing what is truth and what is speculation.  In essence, recognizing what we know and what we don't know.  And part of the process is recognizing that speculation can work both ways--that, paradoxically, the opposite of "false doctrine" may also be "false doctrine".