Joan Robinson, in her book Economic Philosophy (1962, pp. 26-28), offers a meditation on how Adam Smith perceived poets and mathematicians-- and then on how economist fall in-between Her argument is that mathematicians have an agreed-upon method for evaluating errors. Poets do not. And economists fall in between--which introduces a personal element into all economic controversies. In the passage that follows, I'm especially fond of two of her comments: 

"[E]conomics limps along with one foot in untested hypotheses and the other in untestable slogans."

"Keynes was singularly free and generous because he valued no one's opinion above his own. If someone disagreed with him, it was they who were being silly; he had no cause to get peevish about it."

Here's the fuller passage. Robinson writes: 
Anyone who says to you: 'Believe me, I have no prejudices,' is either succeeding in deceiving himself or trying to deceive you. ... [I]n the social sciences, first, the subject-matter has much greater political and ideological content, so that other loyalties are also involved; and secondly, because the appeal to 'public experience' can never be decisive, as it is for the laboratory scientists who can repeat each other's experiments under controlled conditions, the social scientists are always left with a loophole to escape through - 'the consequences that have followed from the causes that I analysed are, I agree, the opposite of what I predicted, but they would have been still greater if those causes had not operated'.

This need to rely on judgement has another consequence. It has sometimes been remarked that economists are more queazy and ill-natured than other scientists. The reason is that, when a writer's personal judgement is involved in an argument, disagreement is insulting.
Robinson then turns to quoting Adam Smith on poets and mathematicians:
Adam Smith [in the Moral Sentiments] remarks upon the different temperaments of poets and mathematicians:

"The beauty of poetry is a matter of such nicety, that a young beginner can scarce ever be certain that he has attained it. Nothing delights him so much, therefore, as the favourable judgements of his friends and of the public; and nothing mortifies him so severely as the contrary. The one establishes, the other shakes, the good opinion which he is anxious to entertain concerning his own performances.

"Mathematicians, on the contrary, who may have the most perfect assurance, both of the truth and of the importance of their discoveries, are frequently very indifferent about the reception which they may meet with from the "public. . . .

"[They] from their independency upon the public opinion, have little temptation to form themselves into factions and cabals, either for the support of their own reputation, or for the depression of that of their rivals. They are almost always men of the most amiable simplicity of manners, who live in good harmony with one another, are the friends of one another's reputation, enter into no intrigue in order to secure the public applause, but are pleased when their works are approved of, without being either much vexed or very angry when they are neglected.

"It is not always the same case with poets, or with those who value themselves upon what is called fine writing. They are very apt to divide themselves into a sort of literary factions; each cabal being often avowedly and almost always secretly, the mortal enemy of the reputation of every other, and employing' all the mean arts of intrigue and solicitation to preoccupy the public opinion in favour of the works of its own members, and against those of its enemies and rivals."
 Robinson then sums up:
Perhaps Adam Smith had rather too exalted a view of mathematicians, and perhaps economists are not quite as bad as poets; but his main point applies. The lack of an agreed and accepted method for eliminating errors introduces a personal element into economic controversies which is another hazard on top of all the rest. There is a notable exception to prove the rule. Keynes was singularly free and generous because he valued no one's opinion above his own. If someone disagreed with him, it was they who were being silly; he had no cause to get peevish about it.

The personal problem is a by-product of the main difficulty, that, lacking the experimental method, economists are not strictly enough compelled to reduce metaphysical concepts to falsifiable terms and cannot compel each other to agree as to what has been falsified. So economics limps along with one foot in untested hypotheses and the other in untestable slogans."