for all I, you, etc. know

for all (one) knows

Said when one is uncertain or has limited details about something. I haven't talked to Marie in weeks, so, for all I know, she's not even coming to the dinner party tonight.
See also: all, know

for all ˈI, ˈyou, etc. know

(spoken) used to emphasize that you somebody does not know something: She could be dead for all I know.
See also: all, know