The best opinion now is, that there are multitudinous forms which are not sufficiently differentiated to be distinctively either plant or animal, while, as respects ordinary plants and animals, the difficulty of laying down a definition has become far greater than ever before.
Asa GrayFaith in order, which is the basis of science, cannot reasonably be separated from faith in an Ordainer, which is the basis of religion.
Asa GrayNatural selection is not the wind which propels the vessel, but the rudder which, by friction, now on this side and now on that, shapes the course.
Asa GrayWe may take it to be the accepted idea that the Mosaic books were not handed down to us for our instruction in scientific knowledge, and that it is our duty to ground our scientific beliefs upon observation and inference, unmixed with considerations of a different order.
Asa Gray