builder makes a house by placing bricks in positions specified by a blueprint. A cook makes a cake not by placing crumbs and currants in specified positions but by putting ingredients through specified procedures, such as sieving, stirring, beating and heating.* Textbooks of biology are wrong when they describe DNA as a blueprint. Embryos do nothing remotely like following a blueprint. DNA is not a description, in any language, of what the finished body should look like.
