The root or truth classification trees. The only constant between the subclasses here is that 1.0 is TRUE, and 0.0 is FALSE. This makes Probability work nicely. Other algebraic tricks may be more appropriate to other version of "truth calculus", but for consistency sake, this value mapping should always be available. For example, the following semantic mappings to simple Booleans always work:<br/><br/>{truthValue() #gt; 0} = possibly true<br/>{truthValue() = 0} = never true<br/><br/>{truthValue() #lt; 1} = possibly false<br/>{truthValue() = 1} = never false<br/><br/>{truthValue() #lt; 1}AND{truthValue() #gt; 0} = uncertain<br/>