This is for any posters who may not have a good grasp of what the term "falsifiability" means in philosophy of science.
http://en.wikipedia.org/wiki/Falsifiability
[Bold emphasis added]
Every assertion of fact about the observable world is falsifiable.
A statement that is not falsifiable is not an assertion of fact about the observable world. It may be an assertion of fact about something that is not observable, or it may be about the observable world but not an assertion of fact.
An example of an assertion of fact about something that is not observable is "Jesus still lives in Heaven." This is an assertion of fact, but as we cannot observe Heaven to ascertain whether or not Jesus still lives there, it isn't about the observable world and therefore is not falsifiable.
An example of a statement about the observable world that is not an assertion of fact is "[You should] do to others as you would have others do to you." This is referring to the observable world, but it makes a claim of value rather than a claim of fact; it is not falsifiable because there is no factual assertion to falsify.
As the quote states, that something is falsifiable doesn't mean it is false. For example, "the moon is in orbit around the Earth" is a falsifiable true statement. If it were false, we could disprove it by observing that there is no moon in orbit around the Earth, and that is what falsifiability means; there is no requirement that a test be performed actually showing that the statement is false (in this case that would be impossible, since the statement
isn't false), only that the statement be of a nature that it
could be proven false if it
were (or is) false. The truth -- a true statement -- can be falsifiable.
Conversely, that a statement is
not falsifiable doesn't mean it is
true. For example, I can state, "The world we observe is actually the Matrix, and we are plugged into a virtual-reality net providing electricity for intelligent machines." This statement is not falsifiable, but we have no reason to believe it is true.
Falsifiability is not falsehood, and non-falsifiability is not truth. (Nor is the other way around the case, i.e., a falsifiable statement is not necessarily true. For example, the falsifiable statement from the quote above that all swans are white is in fact a false statement.)
A non-falsifiable statement is not a statement of fact about the observable world, but it may be an important assertion; certainly values statements are important assertions. However, any such statement occupies a different epistemic category from falsifiable assertions and requires a different criterion for judgment. A non-falsifiable, non-fact assertion cannot be true or false, but it can be valid or invalid.
The important thing is not to confuse these different epistemic categories. It's important to ask whether a statement that is not falsifiable,
should be falsifiable. If it's an assertion of value, then the answer is no, and its non-falsifiability isn't a problem because we're not asking whether it's true or false. If it's a claim of fact, however, then the answer is yes, and if it is non-falsifiable then there is a problem with it. Thus, when someone makes a non-falsifiable assertion, it's important to clarify which of these sorts of statement it is.