It is probably the case that John took the football. It is impossible that Mary went to the bedroom. We doubt that Bernhard is yellow. It is almost certain that if 'Mary went to the bedroom' or 'John took the football' or both then Sandra grabbed the apple. There is a better than even chance that if 'Bernhard is yellow' or 'John took the football' or both then Brian is a lion. We believe that if 'Bernhard is yellow and John took the football' then Gertrude is a mouse.
It is probably the case that 'Gertrude is a mouse and Brian is a lion'.
It is highly unlikely that 'Gertrude is a mouse and Brian is a lion'.
It is probably the case that 'Gertrude is a mouse and Brian is a lion'.

  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
  0.7::factA.
  0.0::factB.
  0.2::factC.
  %hop1
  0.95::factX:-or(factB,factA).
  0.6::factY:-or(factC,factA).
  0.75::factZ:-and(factC,factA).

  %hop2
  conclusion:-and(factZ,factY).

  query(conclusion).
  
'Gertrude is a mouse and Brian is a lion'.