The hypothesis respecting the past history of Nature, which was formerly, and is still very largely, accepted by Christians, is the doctrine fully and clearly stated in the immortal poem of John Milton--the English Divina Commedia--Paradise Lost. There is the best of reasons for the popularity of this doctrine. It agrees literally with the plain words of the Bible. The hypothesis is briefly this: "That this visible universe of ours came into existence at no great distance of time from the present, and that the parts of which it is composed made their appearance, in a certain definite order, in the space of six natural days, in such a manner that on the first of these days light appeared; that on the second the firmament or sky separated the waters above from the waters beneath the firmament; that on the third day the waters drew away from the dry land, and upon it a varied vegetable life, similar to that which now exists, made its appearance; that the fourth day was signalised by the apparition of the sun, the stars, the moon, and the planets; that on the fifth day aquatic animals originated within the waters; that on the sixth day the earth gave rise to our four-footed terrestrial creatures, and to all variations of terrestrial animals except birds, which had appeared on the preceding day; and, finally, that man appeared upon the earth, and the emergence of the universe from chaos was finished." [151] This interpretation is that which has been instilled into most of us in our childhood; but, "if we are to listen to many expositors of no mean authority, we must believe that what seems so clearly defined in Genesis--as if very great pains had been taken that there should be no possibility of mistake--is not the meaning of the text at all. The account is divided into periods that we may make just as long or as short as convenience requires. We are also to understand that it is consistent with the original text to believe that the most complex plants and animals may have been evolved by natural processes, lasting for millions of years, out of structureless rudiments. A person who is not a Hebrew scholar can only stand aside and admire the marvellous flexibility of a language which admits of such diverse interpretations." [152]