It is probably not the case that Brian is white. It is probably the case that Winona is a wolf. We doubt that Bernhard is green. Chances are about even that if 'Bernhard is green and Winona is a wolf' then John discarded the apple. We doubt that if 'Winona is a wolf and Brian is white' then Mary went to the office. It is improbable that if 'Bernhard is green' or 'Winona is a wolf' or both then Lily is yellow.
Chances are slight that 'John discarded the apple' or 'Mary went to the office' or both.
Chances are slight that 'John discarded the apple' or 'Mary went to the office' or both.
It is likely that 'John discarded the apple' or 'Mary went to the office' or both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.25::factA.
  0.7::factB.
  0.2::factC.
  %hop1
  0.5::factX:-and(factC,factB).
  0.2::factY:-and(factB,factA).
  0.1::factZ:-or(factC,factB).

  %hop2
  conclusion:-or(factX,factY).

  query(conclusion).
  
'John discarded the apple' or 'Mary went to the office' or both.