Turning from abstract mathematical and moral relations to concrete relations of coexistence and succession among phenomena - the third sort of knowable relation - Locke finds the light of pure reason disappear; although these relations form " the greatest and most important part of what we desire to know."
So with coexistence and reciprocity.
Thenceforward he devoted his whole time to a systematic examination of the French caves, his first publication on the subject being The Antiquity of Man in Western Europe (1860), followed in 1861 by New Researches on the Coexistence of Man and of the Great Fossil Mammifers characteristic of the Last Geological Period.
For this very reason Orthodox Eastern Christians of alien race felt compelled to resist Greek domination by means of independent ecclesiastical organization, and the structure of the church rather favoured than interfered with the coexistence of separate national churches professing the same faith.
No fact contains in itself the ground of any other; the existence of the facts is due to God, their sequence and coexistence are also due to him.