With such gibes at the term “conception,” he shows, to the best of his ability, that it is useless and unprofitable for the life of man. What, then, was the origin of our higher branches of learning, of geometry, arithmetic, the logical and physical sciences, of the inventions of mechanical art, of the marvels of measuring time by the brazen dial and the water-clock? What, again, of ontology, of the science of ideas, in short of all intellectual speculation as applied to great and sublime objects? What of agriculture, of navigation, and of the other pursuits of human life? how comes the sea to be a highway for man? how are things of the air brought into the service of things of the earth, wild things tamed, objects of terror brought into subjection, animals stronger than ourselves made obedient to the rein? Have not all these benefits to human life been achieved by conception? For, according to my account of it, conception is the method by which we discover things that are unknown, going on to further discoveries by means of what adjoins to and follows36 The definition of ἐπίνοια, i.e. ἔφοδος εὑρετικὴ τῶν ἀγνοουμένων, διὰ τῶν προσεχῶν τε καὶ ἀκολούθων…τὸ ἐφέξῆς ἐξευρίσκουσα from our first perception with regard to the thing studied. For when we have formed some idea of what we seek to know, by adapting what follows to the first result of our discoveries we gradually conduct our inquiry to the end of our proposed research.
ἐν τούτοις καταπαίξας τοῦ τῆς ἐπινοίας ὀνόματος ἄχρηστον αὐτὴν καὶ ἀνόνητον τῷ βίῳ τὸ κατ' αὐτὸν ἀποδείκνυσιν. πόθεν οὖν τῶν μαθημάτων τὰ ὑψηλότερα, πόθεν ἡ γεωμετρία καὶ ἡ ἀριθμητικὴ φιλοσοφία καὶ τῶν λογικῶν τε καὶ φυσικῶν θεωρημάτων ἡ διδασκαλία, αἱ δὲ τῶν μηχανημάτων εὑρέσεις καὶ τὰ διὰ χαλκοῦ τε καὶ ὕδατος ἐν ὡροσκοπείοις θαύματα, αὐτὴ δὲ ἡ περὶ τοῦ ὄντος φιλοσοφία καὶ ἡ τῶν νοητῶν θεωρία καὶ συλλήβδην φάναι πᾶσα ἡ περὶ τὰ μεγάλα τε καὶ ὑψηλὰ τῆς ψυχῆς ἀσχολία; τί δὲ ἡ γεωργία, τί δὲ ἡ ναυτιλία, τί δὲ ἡ λοιπὴ κατὰ τὸν βίον ἡμῶν οἰκονομία; πόθεν βάσιμος τῷ ἀνθρώπῳ ἡ θάλασσα; πῶς δεδούλωται τῷ χερσαίῳ τὸ ἐναέριον, πῶς τιθασσεύεται τὸ ἀνήμερον, πῶς δαμάζεται τὸ φοβερώτερον, πῶς οὐκ ἀφηνιάζει τὸ ἰσχυρότερον; ἆρ' οὐ δι' ἐπινοίας ἐφευρέθη ταῦτα πάντα τῇ ἀνθρωπίνῃ ζωῇ; ἔστι γὰρ κατά γε τὸν ἐμὸν λόγον ἡ ἐπίνοια ἔφοδος εὑρετικὴ τῶν ἀγνοουμένων, διὰ τῶν προσεχῶν τε καὶ ἀκολούθων τῇ πρώτῃ περὶ τὸ σπουδαζόμενον νοήσει τὸ ἐφεξῆς ἐξευρίσκουσα. νοήσαντες γάρ τι περὶ τοῦ ζητουμένου τῇ ἀρχῇ τοῦ ληφθέντος διὰ τῶν ἐφευρισκομένων νοημάτων συναρμόζοντες τὸ ἀκόλουθον εἰς τὸ πέρας τῶν σπουδαζομένων τὴν ἐγχείρησιν ἄγομεν.