I suppose the process of acceptance will pass through the usual four stages:
(i) this is worthless nonsense;
(ii) this is an interesting, but perverse, point of view;
(iii) this is true, but quite unimportant;
(iv) I always said so.

Haldane may have been putting his own twist on a phrase he had heard elsewhere, since similar statements can be found earlier. On p. 113 of The Art of Scientific Investigation (1955), William Ian Beardmore Beveridge wrote: It has been said that the reception of an original contribution to knowledge may be divided into three phases: during the first it is ridiculed as not true, impossible or useless; during the second, people say that there may be something in it but it would never be of any practical use; and in the third and final phase, when the discovery has received general recognition, there are usually people who say that it is not original and has been anticipated by others. | A note at the bottom of the page adds that "This saying seems to have originated from Sir James Mackenzie (The Beloved Physician, by R. M. Wilson, John Murray, London)". In addition, on p. 366 of "The Accident Prevention Problem in the Small Shop" in Safety Engineering Vol. 33 (1950), Earl B. Morgan wrote: First, it is ridiculed; second, it is subject to argument: third, it is accepted. | A similar quote is also often attributed to Arthur Schopenhauer but this is likely incorrect since it does not appear in any of his published writings.