It is likely that Jason is tired. It is probably the case that Greg is white. It is probably not the case that John took the apple. It is highly likely that if 'Greg is white and Jason is tired' then Mary is in the school. We doubt that if 'John took the apple' or 'Jason is tired' or both then Lily is yellow. There is a very good chance that if either 'Greg is white' or 'Jason is tired' but not both then Yann is thirsty.
It is highly likely that 'Greg is white' or 'Jason is tired' or both.
It is highly likely that 'Greg is white' or 'Jason is tired' or both.
It is highly unlikely that 'Greg is white' or 'Jason 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.
  0.25::factC.
  %hop1
  0.9::factX:-and(factB,factA).
  0.2::factY:-or(factC,factA).
  0.8::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Greg is white' or 'Jason is tired' or both.