The Principle of Continuance is analytically true, Immanuel Kant points out that no metaphysical knowledge would be gained in establishing it. A. N. Whitehead's view and the views just considered show alternatives to the Principle of Continuance which can be formulated without inconsistency. What is instructive about them is that they pose the question how it can be made out which alternative is true. Modern geometry constructs interesting alternative self-consistent systems incompatible with one another. Similarly, Whitehead presents his doctrine as a speculative hypothesis. Kemp Smith translates the Principle of Continuance as stating, 'In all change of appearances substance is permanent. The argument which Kant presents for the principle must remain a sealed book to any reader who is acquainted only with Kemp Smith's translation. Kemp Smith translates 'Wechsel' as 'change' and 'Veränderung' as 'alteration'. Empirical knowledge is knowledge which determines an object by means of observations'.