example of an intensional predicate "believesHeWitnessed"

example.ttl

prefix : <>
:fred :believesHeWitnessed  [ a :Marriage ;
                               :hasStart :x ;
                               :groom :m ;
                               :bride :a
                             ]

:a a :Human ;
   :name "Alice" .
:m a :Human .

:b a :RobotPretendingToBeAHuman ;
   :name "X12-101" ;
   :alias "Alice" .

# :fred believes he witnessed a marriage between two humans.
# Even if :a turns out to be :b, because the predicate :believesHeWitnessed is intensional it would be wrong to
# replace :a with :b in that :Marriage because :fred might not believe that :a is really :b.

example in reply to:
https://twitter.com/klinovp/status/1438040489110953985?s=20