context: It is likely that Greg is a swan. It is unlikely that John went to the bedroom. It is likely that Brian is a rhino. There is little chance that if 'Brian is a rhino' or 'Greg is a swan' or both then Julius is a frog. There is almost no chance that if either 'Greg is a swan' or 'John went to the bedroom' but not both then Sandra is in the kitchen. It is highly unlikely that if 'John went to the bedroom and Greg is a swan' then Mary dropped the apple.
hypothesis: It is probable that 'John went to the bedroom and Julius is a frog'.
valid_hypothesis: There is almost no chance that 'John went to the bedroom and Julius is a frog'.
invalid_hypothesis: It is probable that 'John went to the bedroom and Julius is a frog'.
problog: 
    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.
    0.2::factB.
    0.7::factC.
    %hop1
    0.1::factX:-or(factC,factA).
    0.02::factY:-xor(factA,factB).
    0.05::factZ:-and(factB,factA).
  
    %hop2
    conclusion:-and(factB,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'John went to the bedroom and Julius is a frog'.