"Truth". A "loaded-language" synonym for "Theory".
A good scientist builds his theory on all the known facts at the time. He adapts/trashes/changes his theories as new facts come to light.
Most religious "Truths" are built on facts that confirm what a person or group has established that they will believe, to the exclusion of opposing facts. Part of the problem lies in that many of the "facts" are in fact unprovable assumptions. Sometimes the evidence is so strong to show that the "truth" is not true, that the "truth" must change.
The difference between a "truth" and "theory" is that you can question a theory and improve on the theory, but you cannot question a "truth" without the threat of disfellowshipping/shunning (unless you recant your position). By calling the "theory" a "truth", you instill raise the barrier for questions, ie "why are you challenging what is known to be true?" Ironically, the leaders are allowed to change the "truth" at any time because they define what the "truth" is.