Fact = Rule with No Premises

(def clauses '((a) (b) (d) (c a b) (e c d)) )

user=> (backch 'e)
TRACE t290: (backch e)
TRACE t291: | (backch c)
TRACE t292: | | (backch a)
TRACE t292: | | => true
TRACE t293: | | (backch b)
TRACE t293: | | => true
TRACE t291: | => true
TRACE t294: | (backch d)
TRACE t294: | => true
TRACE t290: => true
true