Paradox of Self-Amendment by Peter Suber 8. Hart, "Self-Referring Laws," Festskrift Tillägnad Karl Olivecrona, Stockholm: Kungl. Boktryckeriet. P.A. Norstedt & Söner, 1964, pp. 307-16, at p. 315. 9. This claim amounts to saying that inferences by modus tollens are not generally valid in law; it is defended at greater length in Section 21.B. 10. Alf Ross, "Self-Reference and a Puzzle in Constitutional Law," Mind, 78 (1969) 1-24, at p. 24. 11. Jeremy Bentham, Anarchical Fallacies, in Bowring ed. of his Works, vol. 2, pp. 501. See also his Pannomial Fragments, vol. 3, p. 221. Quoted by H.L.A. Hart in "1776-1976: Law in the Perspective of Philosophy," in his Essays in Jurisprudence and Philosophy, Oxford University Press, 1983, pp. 145-58 at p. 147. 12. Ross, ibid., at p. 21. 13. We may regard this agreement as a sufficient authority by itself or as an authority only by virtue of a rule of public law that gives agreement this status. Some of the difficulties of the latter position are discussed in Sections 7 and 20. 14. Ross, ibid., at p. 6. 34