Many of the conclusions to which I have been led run counter to opinions which have been widely held

From the preface to The Great Depression by Lionel Robbins, published in 1934.  

THE following pages make no claim to present an exhaustive account of the events with which they deal.  Nor do they set out in full rigour the various analytical theorems upon which they are based. They are merely an attempt, with the aid of what is sometimes called "orthodox" economics, to furnish a succinct commentary on the more conspicuous features of the slump and its antecedents. In doing this I have been most acutely aware of the difficulties of the task I have undertaken. The subject is highly controversial, and many of the conclusions to which I have been led run counter to opinions which have been widely held, at any rate in this country. I put them forward, not with any confidence whatever in the superiority of my own judgment, but in the belief that the point of view from which they spring, which is not specifically my own but is the heritage of generations of subtle and disinterested thought, is a point of view whose applicability to the interpretation of the bewildering problems with which we are now confronted has not as yet been sufficiently recognised.

The events and casual mechanisms are still being debated these ninety some years later.   Still, it is nice call for modesty of conviction when dealing with empirical data and complex issues.  What we do not understand usually materially outweighs that with which can believe with justifiable conviction.