There are many truths of which the full meaning cannot be realised, until personal experience has brought it home - John Stuart Mill

He who knows only his own side of the case, knows little of that. His reasons may be good, and no one may have been able to refute them. But if he is equally unable to refute the reasons on the opposite side; if he does not so much as know what they are, he has no ground for preferring either opinion.

الأمة التي تُقَزِّم رجالها، لكي يصبحوا أدوات طيعة أكثر في يديها حتى من أجل أهداف مفيدة، سوف تجد أنه لا يمكن إنجاز شيئ عظيم برجال صغار

So long as an opinion is strongly rooted in the feelings, it gains rather than loses in stability by having a preponderating weight of argument against it.