As the pedants among us never tire of pointing out, the so-called "Nobel Prize in economics" is not literally a "Nobel prize." It was not established by the original bequest from Alfred Nobel, but instead was first given in 1969, with the prize money provided by a grant from Sweden's central bank as part of the 300th anniversary of the founding of the bank. Thus, the award is officially "The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel." (Justin Fox gives a nice brief overview of the history here.) Although I am pedantic in many matters, this doesn't happen to be one of them, so I will continue following the conventional usage in calling it the "Nobel prize in economics."
More interesting is that Friedrich Hayek the co-winner of the sixth Nobel prize in economics (with Gunnar Myrdal), spoke at the prize banquet in 1974 as to why the establishment of the prize was mistaken. Here's is Hayek's call to humility for economists from his speech at the Nobel banquet on December 10, 1974.
Your Majesty, Your Royal Highnesses, Ladies and Gentlemen,
Now that the Nobel Memorial Prize for economic science has been created, one can only be profoundly grateful for having been selected as one of its joint recipients, and the economists certainly have every reason for being grateful to the Swedish Riksbank for regarding their subject as worthy of this high honour.
Yet I must confess that if I had been consulted whether to establish a Nobel Prize in economics, I should have decidedly advised against it.
One reason was that I feared that such a prize, as I believe is true of the activities of some of the great scientific foundations, would tend to accentuate the swings of scientific fashion. This apprehension the selection committee has brilliantly refuted by awarding the prize to one whose views are as unfashionable as mine are.
I do not yet feel equally reassured concerning my second cause of apprehension. It is that the Nobel Prize confers on an individual an authority which in economics no man ought to possess.
This does not matter in the natural sciences. Here the influence exercised by an individual is chiefly an influence on his fellow experts; and they will soon cut him down to size if he exceeds his competence.
But the influence of the economist that mainly matters is an influence over laymen: politicians, journalists, civil servants and the public generally. There is no reason why a man who has made a distinctive contribution to economic science should be omnicompetent on all problems of society - as the press tends to treat him till in the end he may himself be persuaded to believe. One is even made to feel it a public duty to pronounce on problems to which one may not have devoted special attention.
I am not sure that it is desirable to strengthen the influence of a few individual economists by such a ceremonial and eye-catching recognition of achievements, perhaps of the distant past.
I am therefore almost inclined to suggest that you require from your laureates an oath of humility, a sort of hippocratic oath, never to exceed in public pronouncements the limits of their competence.
Or you ought at least, on confering the prize, remind the recipient of the sage counsel of one of the great men in our subject, Alfred Marshall, who wrote: "Students of social science, must fear popular approval: Evil is with them when all men speak well of them".
Hayek is quoting from an comment from Marshall which appears in "In Memoriam: Alfred Marshall," a speech given by A.C. Pigou in 1924 and published as part of a Memorials of Alfred Marshall volume in 1925 (pp. 81-90). The fuller quotation attributed to Marshall (on p. 89) is:
Students of social science, must fear popular approval: Evil is with them when all men speak well of them. If there is any set of opinions by the advocacy of which a newspaper can increase its sales, then the student who wishes to leave the world in general and his country in particular better than it would have been if he had not been born, is bound to dwell on the limitations and defects and errors, if any, in that set of opinions: and never to advocate them unconditionally even in ad hoc discussion. It is almost impossible for a student to be a true patriot and to have the reputation of being one in his own time.