 It seems that Wheeler was right. Roux, Weismann, and others had decided that development must be guided by predetermined mosaic differences. Preformation, stability, and predictability stood on one side, with epigenesis, dynamic process, and change on the other. And, as Wheeler noted, by 1899 the way forward lay between the extremes of strict preformation or epigenesis. Wheeler’s dissertation director Charles Otis Whitman agreed. Whitman felt that what biology needed was a clear statement of the alternative views, and then movement to a new standpoint examining how much depends on the organism’s developmental response to external conditions drawing on preformation, rather than on programmed internal unfolding alone.