But we must here observe that, although we are already certain that the mind is eternal, in so far as it conceives things under the form of eternity, yet, in order that what we wish to show may be more readily explained and better understood, we will consider the mind itself, as though it had just begun to exist and to understand things under the form of eternity, as indeed we have done hitherto; this we may do without any danger of error, so long as we are careful not to draw any conclusion, unless our premisses are plain.