The fourth position is the coping-stone of Kant's metaphysics.
Gradually, however, he was made uneasy by the obvious trend of the imperial policy towards the annihilation of Protestantism, and by a dread lest the ecclesiastical lands should be taken from him; and the issue of the edict of restitution in March 1629 put the coping-stone to his fears.
For example, if a body, say a coping-stone, has been thrown horizontally through a distance a, and fallen from a height b, the maximum horizontal velocity with which it was projected equals !
In a sense this theory puts the coping-stone upon Christological development.