In this work I will try to show that Stephen Toulmin's notion of an ideal of natural order could be very useful to characterize the clash between the orthodox Neo-Darwinism and the evolutionary developmental biology, or evo-devo, that today seems to affect the very foundations of the new synthesis. The works in evo-devo, I will say, lead to re-examinate the relation between ontogeny and phylogeny in a way that supposes a displacement of which I will characterize as the classic Darwinism's ideal of natural order. Thus, after trying to identify this last ideal of natural order, I will try to identify the alternative ideal of natural order to which the present researches in evo-devo would obey.
Evolutionary developmental biology; Evo-devo; Ideal of natural order; Neo-Darwinism; Toulmin