It so often happens that a well-crafted argument is no match for a well-established sentiment, such that in controversy, a resistance is put up, whereby the stronger the opposing case, the firmer one’s resolve to oppose it. As Sydney Smith told Lord John Russell,
Euclid would have had a bad chance with you if you had happened to have formed an opinion that the interior angles of a triangle were not equal to two right angles. The more poor Euclid demonstrated, the more you would not have been convinced. 
That of course is an exaggeration designed to make a point about Lord Russell’s obstinacy. In many things, however, in which sentiments and the undemonstrables of life might figure more prominently, it is often the case that the belief comes first, and the reasons for believing come later, and that for the whole edifice, it is sentiment that provides the foundations, with reasons (truth-claims and arguments) as the supports.
.....One may try to kick away the supports, but they are likely to be strongly embedded in the foundations; and even if one manages to kick them away, and the roof comes crashing in, there is no certainty that a man will abandon the foundations to begin anew elsewhere. It is just as likely that he will retain his attachment to them and go in search of new supports. Often then, if you wish in controversy to get a man to abandon his beliefs, you must take dynamite to his sentiments—and this explosive is often made, not from reason or facts, but from other sentiments.
.....It is often said—more from affectation than conviction—that sentiment is always a very poor thing on which to base one’s arguments, and no doubt in many instances, sentiment should play no part. One could draw only puzzled glances and pitying looks if one were to argue that the sky is blue because it looks rather nice that way. Without sentiment, however, most people would find no persuasive grounds for the assertion that people should not be tortured for fun. The belief is ultimately rational, but for most it comes immediately and unreflectively from sentiment. The sadist too is a sentimentalist.
.....The existence of sentiment in controversy can be both a blessing and a curse. On the one hand, shared sentiment provides us with grounds from which we might persuade others of the goodness of a belief. On the other hand, it may introduce perverse and almost immovable objections to the most evident truths.
.....The most interminable controversies are usually those which surround the question of how society and government ought to be organised; for, though truth and sound reasoning may be brought to bear, it is sentiment that often plays the role in immediately determining what a person feels to be the better way of life, and thus it is a matter over which the twain shall rarely meet.
.....In such cases, and if one insists in arguing it out, one of the most effective things to do against an advocate of a certain way of life is to demonstrate to him that it will bring about circumstances which will be an affront to the very sentiments by which he advocates it in the first place. I do not predict much controversy when I say that this is more easily said than done.
 Sydney Smith, quoted by Hesketh Pearson, The Smith of Smiths, Being the Life, Wit and Humour of Sydney Smith. The Right Book Club, London. (n.d.). p. 274.