In terms of topics treated, the Philosophy of Nature largely coincides with those treated in the third book of the Science of Logic when the logical processes and relations in question have returned to objectivity after the excursion into the subjectivity of formal logic at the outset of Book 3.  In Mechanism Hegel had reconstructed a movement in thought from a primitive cosmology in which all objects are conceived in relation to a central object (the sun) that exemplifies objecthood per se, to a system of objects within which any such self-sufficient center has been eliminated. In this Newtonian world, that which gives order to the whole now has the ideality of law, but this is itself thought of as external to the system of objects.