context: It is probable that Mary went to the hallway. It is almost certain that Fred moved to the office. Chances are about even that John took the football. It is almost certain that if 'Fred moved to the office and Mary went to the hallway' then Lily is white. It is unlikely that if 'Mary went to the hallway and John took the football' then Bernhard is a lion. It is unlikely that if 'John took the football and Fred moved to the office' then Yann is hungry.
hypothesis: It is probably the case that 'Fred moved to the office and Mary went to the hallway'.
valid_hypothesis: It is probably the case that 'Fred moved to the office and Mary went to the hallway'.
invalid_hypothesis: There is little chance that 'Fred moved to the office and Mary went to the hallway'.
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.
    0.95::factB.
    0.5::factC.
    %hop1
    0.95::factX:-and(factB,factA).
    0.2::factY:-and(factA,factC).
    0.2::factZ:-and(factC,factB).
  
    %hop2
    conclusion:-and(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Fred moved to the office and Mary went to the hallway'.