There is a very good chance that Bernhard is a swan. We doubt that Brian is green. It is highly likely that Julius is a lion. We doubt that if 'Julius is a lion and Brian is green' then Jeff moved to the office. It is probable that if 'Julius is a lion' or 'Brian is green' or both then John picked up the apple. It is impossible that if 'Brian is green and Julius is a lion' then Lily is gray.
There is little chance that 'Brian is green' or 'John picked up the apple' or both.
It is likely that 'Brian is green' or 'John picked up the apple' or both.
There is little chance that 'Brian is green' or 'John picked up the apple' 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
  0.8::factA.
  0.2::factB.
  0.9::factC.
  %hop1
  0.2::factX:-and(factC,factB).
  0.7::factY:-or(factC,factB).
  0.0::factZ:-and(factB,factC).

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

  query(conclusion).
  
'Brian is green' or 'John picked up the apple' or both.