; Create the knowledge base as a global list

(setq *kb* '(
  (s2 c)
  (t1 c)
  (t2 d)
  (r1 b)
  (r3 b)
  (if (and (p1 a) (p2 a)) (q x))
  (if (and (r1 b) (r2 b)) (q x))
  (if (and (t1 c) (t3 d) (p1 a)) (u y))
  (if (and (u y) (t1 c)) (v y))
  (if (t2 d) (t3 d))
  (if (p2 b) (r2 b))
  (if (s1 c) (p1 a))
  (if (s2 c) (p1 a))
  (if (and (r1 b) (t1 d)) (p2 a))
  (if (and (r3 b) (t2 d)) (p2 b))
  ))

; Explain some potential conclusions

(explain-why '(r1 b))
(explain-why '(s2 b))
(explain-why '(p1 a))
(explain-why '(p2 a))
(explain-why '(p2 b))
(explain-why '(q x))
(explain-why '(v y))