Now if one thinks that there could be no understanding and obeying the order without a previous teaching, one thinks of the teaching as supplying a reason for doing what one did; as supplying the road one walks. Now there is the idea that if an order is understood and obeyed there must be a reason for our obeying it as we do; and in fact, a chain of reasons reaching back to infinity. This is as if one said: “Wherever you are, you must have got there from somewhere else, and to that previous place from another place; and so on ad infinitum”. (If, on the other hand, you had said, “wherever you are, you could have got there from another place ten yards away; and from that other place from a third, ten yards further away, and so on ad infinitum”, what then you would have stressed would have been the infinite possibility of making a step. Th[i|u]s

23.

the idea of an infinite chain of reasons arises out of a confusion similar to this:– that a line of a certain length consists of an infinite number of parts because it is indefinitely divisible; i.e. because there is no end to the possibility of dividing it.)

(2015–) Wittgenstein Source Bergen Nachlass Edition (WS-BNE). Edited by the Wittgenstein Archives at the University of Bergen under the direction of Alois Pichler. In: Wittgenstein Source, curated by Alois Pichler (2009–) and Joseph Wang-Kathrein (2020–). (N) Bergen: WAB.