καίτοι φαμὲν τοῦτ᾿ εἶναι τῶν κινουμένων καὶ κινούντων ἀρχήν, καὶ πρῶτον τοῖς κινουμένοις τὸ αὐτὸ αὑτὸ κινοῦν.
᾿Αριστοτέλης
Why is there something rather than nothing? The sufficient reason is found in a substance that is a necessary being, carrying the reason for its existence with itself.
Leibniz
David Gunn 