The known false block is located in the Logic drawer of the Blawx toolbox.
The known false block is used to specify that the statement it contains is known with certainty to be false.
The known false block is a statement that can be stacked with other statements.
The known false block accepts an external connection which must be a single statement.
The known false block is one of two forms of negation in Blawx. The other is the not block.
The not block and the known false block differ in that the known false block asserts that something is false, while the not block asserts only that it is either false, or the truth of the statement is impossible to prove.
The known false block is not usually going to be used in rules, and is more common to use in facts.
If you are not sure which negation block to use, start with "not."
One way to think of the difference between "known false" and "not" is by looking at the difference between "not guilty" and "innocent" in criminal law.
Courts don't typically find accused "innocent", because that would be to say that they know, as a fact, that it is not true that the party is guilty. They typically find people "not guilty", which means they may or may not be guilty, but there was not enough evidence to prove it.
If "guilty" was an attribute in Blawx, "not guilty" would be wrapping the "guilty" attribute In a "not" block, and "innocent" would be wrapping guilty in a "known false" block.