Inside Chesterton’s work, "Orthodoxy" can be considered like a summary of his philosophy.

This book is composed of several criticisms of the differents drifts of thought in his age.

In the first place, Chesterton begins with a criticism of the person who guides his life just by the way of the Reason. It is a criticism of rationalism and materialism: spirit versus matter.

‘Indeed, the common phrase for insanity is in this respect a misleading one. The madman is not the man who has lost his reason. The madman is the man who has lost everything except his reason’.

‘The madman’s explanation of a thing is always complete, and often in a purely rational sense satisfactory. Or, to speak more strictly, the insane explanation, if not conclusive, is at least unanswerable; this may be observed specially in the two or three commonest kinds of madness’

Chesterton defines madness as:

‘We may say in summary that it is reason used without root, reason in the void. The man who begins to think without the proper first principles goes mad; he begins to think at the wrong end.’

According to Chesterton, man needs an interior balance. This equilibrium is mantained because of the small mistic part that always remained in him.

The misticism’s secret is this:

‘That man can understand everything by the help of what he does not understand. The morbide logician seeks to make everything lucid, and succeeds in making everything mysterious. The mistic allows one thing to be mysterious, and everything else becomes lucid.’

Finally Chesterton affirms that the base of madness is not the imagination’s excess, but the Reason’s one.

In the second chapter, Chesterton writes about the difference between humility and haughtiness. Humility has been always understood as a limitation of haughtiness.

But, after:

‘But what we suffer from to-day is humility in the wrong place. Modesty has moved from the organ of ambition. Modesty has settled upon the organ of conviction; where it was never meant to be.

A man was meant to be doubtful about himself, but undoubting about the truth; this has been exactly reversed. Nowadays the part of a man that a man does assert is exactly the part he ought not to assert himself. The part he doubts is exactly the part he ought not to doubt--- the Divine Reason.

Huxley preached a humility content to learn from Nature. But the new sceptic is so humble that he doubts if he can even learn.’

Afterwards, Chesterton criticizes the evolutionism tendency. According him, the evolutionism is an strong attack against

rationalism, and not against Christianism as always was thought:

‘Evolution is a good example of that modern intelligence which, if it destroys anything, destroys itself. If evolution destroys anything, it does not destroy religion but rationalism.’

‘At best, there is only one thing, and taht is a flux of everything and anything. This is an attack not upon the faith, but upon the mind; you cannot think if there are no things to think about.’

In another chapter, Chesterton remarks the importance of democracy and the its compatibility with tradition. According to the main thinkers of his age, democracy is opposite to tradition. Chesterton says that democracy in the fact is no other thing that tradition planned in the time.

Chesterton also makes a criticism from children’s stories comparing them to materialism, the own existence and the philosophy of Nietzsche:

‘In fairyland we avoid the word "law"; but in the land of science they are singularly fond of it. Thus they call some interesting conjecture about how forgotten folks pronounced the alphabet, Grimm’s Law. But Grimm’s Law is far less intellectual than Grimm’s Fairy Tales. The tales are, at any rate, certainly tales; while the law is not a law. A law implies that we know the nature of the generalisations and enactment; not merely that we have noticed some of the effects.’

‘This incidentally, is almost the whole weakness of Nietzsche, whom some are representing as a bold and strong thinker.

No one will deny that he was a poetical and suggestive thinker; but he was quite the reverse of strong. He was not at all bold. He never put his own meaning before himself in bald abstract words: as did Aristotle and Calvin, and even Karl Marx, the hard, fearless men of thought.’

In other chapter, Chesterton makes a thorough study about christian religion. It is not a treatice about faith, neither an apology of christianism but an objective research about why christianism had such a contradictory role in History:

‘The very people who reproached Christianity with the meekness and non-resistance of the monasteries were the very people who reproached it also with the violence and valour of crusades.’

Chesterton compares christianism to other ideological and religious movements:

‘Paganism declared that virtue was in a balance; Christianity declared it was in a conflict: the collision of two passions apparently opposite. Of course they were not really inconsistent; but they were such that it was hard to hold simultaneously.’

‘Thi is the intellectual abyss between Buddhism and Christianity; that for the Buddhist or Theosophist personality is the fall of the man, for the Christian it is the purpose of God, the whole point of his cosmic idea. The world-soul of the Theosophists ask man to love it only in order that man may throw himself into it. But the divine centre of Christianity actually threw man out of it in order that he might love it.’

Little by little, Chesterton arrives to the conclusion that really christianism is the right ideology, ‘The right side’, that makes you able to keep the inner balance.

He doesn’t get to this conclusion guided by his beliefs, in a subjective way; he follows the common sense.

He starts from a objective base, and contrast the different ideologies looking for what he consideres balanced, but always from a rational point of view.