Chesterton on being broad-minded

A good bit from chapter 20 of G. K. Chesterton’s Heretics:

Whether the human mind can advance or not, is a question too little discussed, for nothing can be more dangerous than to found our social philosophy on any theory which is debatable but has not been debated. But if we assume, for the sake of argument, that there has been in the past, or will be in the future, such a thing as a growth or improvement of the human mind itself, there still remains a very sharp objection to be raised against the modern version of that improvement. The vice of the modern notion of mental progress is that it is always something concerned with the breaking of bonds, the effacing of boundaries, the casting away of dogmas. But if there be such a thing as mental growth, it must mean the growth into more and more definite convictions, into more and more dogmas. The human brain is a machine for coming to conclusions; if it cannot come to conclusions it is rusty. When we hear of a man too clever to believe, we are hearing of something having almost the character of a contradiction in terms. It is like hearing of a nail that was too good to hold down a carpet; or a bolt that was too strong to keep a door shut. Man can hardly be defined, after the fashion of Carlyle, as an animal who makes tools; ants and beavers and many other animals make tools, in the sense that they make an apparatus. Man can be defined as an animal that makes dogmas. As he piles doctrine on doctrine and conclusion on conclusion in the formation of some tremendous scheme of philosophy and religion, he is, in the only legitimate sense of which the expression is capable, becoming more and more human. When he drops one doctrine after another in a refined scepticism, when he declines to tie himself to a system, when he says that he has outgrown definitions, when he says that he disbelieves in finality, when, in his own imagination, he sits as God, holding no form of creed but contemplating all, then he is by that very process sinking slowly backwards into the vagueness of the vagrant animals and the unconsciousness of the grass. Trees have no dogmas. Turnips are singularly broad-minded.