Example I'm at work,neighbor John calls to say my alarm is ringing,but neighbor Mary doesn't call.Sometimes it's set off by minor earthquakes.Is there a burglar? Variables:Burglary,Earthquake,Alarm,JohnCalls,MaryCalls Network topology reflects "causal"knowledge: A burglar can set the alarm off An earthquake can set the alarm off The alarm can cause Mary to call The alarm can cause John to call Example • I'm at work, neighbor John calls to say my alarm is ringing, but neighbor Mary doesn't call. Sometimes it's set off by minor earthquakes. Is there a burglar? • Variables: Burglary, Earthquake, Alarm, JohnCalls, MaryCalls • Network topology reflects "causal" knowledge: – A burglar can set the alarm off – An earthquake can set the alarm off – The alarm can cause Mary to call – The alarm can cause John to call