Once the idealist argument is accepted, I understand that it is possible—even inevitable —to go even further. . . . The Cartesian "I think, therefore I am" is thus invalidated: to say I think is to postulate the I, and is a petito principii. In the eighteenth century, Lichtenberg proposed that in place of I think, we should say, impersonally it thinks, just as one could say it thunders or it flashes (lightning).
--Jorge Luis Borges, "A New Refutation of Time"