\Dys*te`le*ol"o*gy\, n. [Pref. dys- + teleology.] (Biol.) The doctrine of purposelessness; a term applied by Haeckel to that branch of physiology which treats of rudimentary organs, in view of their being useless to the life of the organism. To the doctrine of dysteleology, or the denial of final causes, a proof of the real existence of such a thing as instinct must necessarily be fatal. --Word (Dynamic Sociology).