It is probably the case that Mary put down the apple. It is probable that Sandra left the football. It is highly likely that Julius is white. It is almost certain that if either 'Mary put down the apple' or 'Julius is white' but not both then Sumit is tired. It is almost certain that if either 'Mary put down the apple' or 'Sandra left the football' but not both then Brian is green. There is almost no chance that if 'Sandra left the football and Julius is white' then Yann is thirsty.
It is probably not the case that 'Yann is thirsty' or 'Sumit is tired' or both.
It is probably not the case that 'Yann is thirsty' or 'Sumit is tired' or both.
We believe that 'Yann is thirsty' or 'Sumit is tired' 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
  0.7::factA.
  0.7::factB.
  0.9::factC.
  %hop1
  0.95::factX:-xor(factA,factC).
  0.95::factY:-xor(factA,factB).
  0.02::factZ:-and(factB,factC).

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

  query(conclusion).
  
'Yann is thirsty' or 'Sumit is tired' or both.