προάγεται δὲ τὸ λογικὸν άπὸ τινος ἐνεργείας ἡμετέρας τοῦτον τὸν τρόπον.
The logical argument is conducted by someone who speaks for us in the following way.
I am not sure I understand ἐνεργείας ἡμετέρας.
I think it means our activity, so the whole sentence would be: the logical argument, with some activities of ours taken as an example, is presented in the following way.