This principle will, I think, help us in trying to solve the question why so few nations have progressed, though to us progress seems so natural-what is the cause or set of causes which have prevented that progress in the vast majority of cases, and produced it in the feeble minority. But there is a preliminary difficulty: What is progress, and what is decline? Even in the animal world there is no applicable rule accepted by physiologists, which settles what animals are higher or lower than others; there are controversies about it. Still more then in the more complex combinations and politics of human beings it is likely to be hard to find an agreed criterion for saying which nation is before another, or what age of a nation was marching forward and which was falling back. Archbishop Manning would have one rule of progress and decline; Professor Huxley, in most important points, quite an opposite rule; what one would set down as an advance, the other would set down as a retreat. Each has a distinct end which he wishes and a distinct calamity which he fears, but the desire of the one is pretty near the fear of the other; books would not hold the controversy between them. Again, in art, who is to settle what is advance and what decline? Would Mr. Buskin agree with anyone else on this subject, would he even agree with himself or could any common enquirer venture to say whether he was right or wrong? I am afraid that I must, as Sir Wm. Hamilton used to say, 'truncate a problem which I cannot solve.' I must decline to sit in judgment on disputed points of art, morals, or religion. But without so doing I think there is such a thing as 'verifiable progress,' if we may say so; that is, progress which ninety-nine hundredths or more of mankind will admit to be such, against which there is no established or organised opposition creed, and the objectors to which, essentially varying in opinion themselves, and believing one thing and another the reverse, may be safely and altogether rejected.