In the paper, they agued that in what they called a "perfect market" (Modigliani and Miller 1958, p. 268) neither the total market value of a corporation (the sum of the market values of its stocks and bonds) nor the average cost' to it of capital was affected by its "capital structure" that is, by the extent to which it finances its activities by borrowing (issuing bonds) rather than by issuing stock.

Donald MacKenzie, An Engine, Not a Camera, loc. 175