To begin with, aside from snow actually being colorless, it is self-referencing. A statement purporting to be logical, that allows no outside information to influence it or be tried against it, is an example of circular reasoning; that is, it sets up its own set of conditions wherein it is true only of it is true. "This sentence is true if, and only if, this sentence is true." Another example of circular reasoning is, “The Bible is true because my preacher says so, and he knows it’s true because he found it in the Bible.”

Such a sentiment shows the original statement to be only an incomplete part of a logical argument. The complete statement includes the reason for making the statement, as in, “Snow is white if, and only if, snow is white; therefore snow is white.” Such a statement leaves us wondering exactly what it's trying to say because it is actually saying nothing much at all. A statement is true only if it can be tested outside of itself. Otherwise, almost any kind of word can be substituted for 'true' and the sentence will work in its own little world: "This sentence is meaningless if, and only if, this sentence is meaningless." "The Bible is meaningless because my preacher said so, and he knows it's meaningless because he found it in the Bible."

Furthermore, the statement offers no method of verification. Introducing new parameters into the simile shows that the statement structure will be true only when our understanding of the terms can agree. “Dogs are cats if, and only if, cats are dogs” is obviously wrong as verified by our understanding of the nature of dogs and cats, even though the maker of the statement would appear to be defending the concept that dogs equal cats. “Dogs are cats if, and only if, cats are dogs; therefore dogs are cats.”

The original statement shows us we cannot always know whether such a statement is wrong just because someone could express it, and that is why it cries for verification before we could even justify considering its merits. Often seen on little hand-painted signs along rural roads is one that proclaims, “God is love.” We can see from the foregoing that switching the subjects would render it as, “Love is God.” We cannot know whether that is true. We most certainly see the opposite when we search for even the most meager examples. Rendering a more complete logical argument into “God is love if, and only if, love is God; therefore God is love” cannot be proven or disproved and so, for so long as it remains unverifiable and unfalsifiable, the Principle of Defeasibility requires it to be abandoned. We must treat it as false until it can be demonstrated otherwise.

Like the sponsors of Intelligent Design, those who make self-evident encapsulated statements believe them to be obviously correct and irrefutable. They decry anyone’s expression of a desire to learn of a use for such a statement. “What good is it to believe that snow is white if, and only if, snow is white? What ‘therefore’ should I arrive at by agreeing with it?” "Therefore, we can leave white places on Xmas cards, and they will be snow?"

Even more, those with whom they disagree are expected to assume such statements to be ‘scientific’ in themselves, and not require them to meet –or even be exposed to– the rigors of scientific testing. Such a statement cannot be tested in any acceptable way I know of. How can it be falsified or verified?

It can't. The author of such a statement is unaware that Argumentum ad Ignorantum (Argument from Ignorance) can go both ways: If something ought not to be deemed obviously false because he knows of no cases in which it can be true, it can also be probable that we must not deem something to be obviously true just because we are aware of no times when it can be false. That is the meat of the defeasibility principle. A skeptical approach to all truisms demands that convincing evidence must accompany any and all claims about ultimate truths. An analytical approach is required to apply defeasibility, which makes that same demand.

Its author would insist that’s unnecessary, that the statement stands alone as correct, no verification needed. We have already seen that to be untrue, but still need a demonstration of why we have to accept it as correct. We need to be shown that, in pitch darkness, where nothing else present could affect our perceptions, it still holds true. Or, in the bowels of a cave, or in the desert at 105º Fahrenheit. Why not shine different colors of light on it to see what happens? Maybe we'll learn what religious people need to know: There is no such thing as a truly self-supporting statement. If a statement does not get verified to show that it holds true under all conditions, it quite likely needs to be very thoroughly tested.

Viewing the snow in darkness shows us the snow has no color of its own. The lights show us the lightwaves (or whatever the current description is) activate sensors in our eyes that cause us to sense colors according to the nature of the light. Snow is actually a colorless substance that appears white because of the way it refracts light that shines on it. That snow may be white if, and only if it is white may never have been actually tested, since the debate ought to be about whether truly white snow has ever been observed. It also may depend on one's interpretation of exactly what is white, what is snow, and what is meant by "only if" and "it".

To make the statement truly logical, however, we must complete it: “Snow is white if, and only if, snow is white” requires an assertion to be included that offers an example of its rectitude before we can finally assume that "therefore, snow is white." "Snow is white if, and only if, snow is white because (parameter), therefore snow is white" is absent the required parameter. We can find that from the preceding information, and insert the requirement that must be true before it can also be assumed true that snow is white even when it appears to be white. I will explain, and then leave that task for you so you can demonstrate to yourself that you do understand.

Snow is crystals of frozen water which, all else being right, is a clear substance. In fact it's transparent, of no color. We know from experience we cannot see through drifts of snow (you folks in the deep south can verify that by the frost in your freezers). We refer to snow as white.

To demonstrate what kind of information parades as an assertion, let's again use substitution to change our so-called factual sentence: "Water is ice if, and only if, ice is water; (parameter); therefore ice is water." Since we already know that ice and frozen water are the same thing, finding the parameter ought to be easy. We only need to ask ourselves why a block of ice is not a puddle.

That we have learned to measure heat (caloric energy) and accordingly know what kinds of phenomena occur at various temperatures tells us our answer. All we have to do is figure out how to formulate an accurate sentence with our information: Using 'equals' for 'is', we can render it into a facsimile of a mathematical statement: "Water minus heat equals ice if, and only if, ice plus heat equals water; ice plus heat does equal water; therefore water equals ice plus heat." That can be tested in many ways and verified as demonstrably true.