We believe that Bernhard is a rhino. Chances are about even that Winona is a mouse. Chances are slight that Lily is a lion. It is likely that if 'Winona is a mouse and Bernhard is a rhino' then John took the apple. There is a better than even chance that if either 'Bernhard is a rhino' or 'Lily is a lion' but not both then Mary moved to the garden. It is improbable that if 'Lily is a lion and Winona is a mouse' then Julius is yellow.
We believe that 'John took the apple' or 'Bernhard is a rhino' or both.
We believe that 'John took the apple' or 'Bernhard is a rhino' or both.
There is almost no chance that 'John took the apple' or 'Bernhard is a rhino' 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
  0.75::factA.
  0.5::factB.
  0.1::factC.
  %hop1
  0.7::factX:-and(factB,factA).
  0.6::factY:-xor(factA,factC).
  0.1::factZ:-and(factC,factB).

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

  query(conclusion).
  
'John took the apple' or 'Bernhard is a rhino' or both.