The Inimitable GK Chesterton
The Sentimentalist, roughly speaking, is the man who wants to eat his cake and have it. He has no sense of honour about ideas; he will not see that one must pay for an idea as for anything else. He will not see that any worthy idea, like any honest woman, can only be won on its own terms, and with its logical chain of loyalty. One idea attracts him; another idea really inspires him; a third idea flatters him; a fourth idea pays him. He will have them all at once in one wild intellectual harem, no matter how much they quarrel and contradict each other. The Sentimentalist is a philosophic profligate, who tries to capture every mental beauty without reference to its rival beauties; who will not even be off with the old love before he is on with the new. Thus if a man were to say, "I love this woman, but I may some day find my affinity in some other woman," he would be a Sentimentalist. He would be saying, "I will eat my wedding-cake and keep it." Or if a man should say, "I am a Republican, believing in the equality of citizens; but when the Government has given me my peerage I can do infinite good as a kind landlord and a wise legislator"; then that man would be a Sentimentalist. He would be trying to keep at the same time the classic austerity of equality and also the vulgar excitement of an aristocrat. Or if a man should say, "I am in favour of religious equality; but I must preserve the Protestant Succession," he would be a Sentimentalist of a grosser and more improbable kind.
This is the essence of the Sentimentalist: that he seeks to enjoy every idea without its sequence, and every pleasure without its consequence.