Full Idea
My I, in efffect, is no more certain for consciousness than the I of other men. It is only more intimate.
Gist of Idea
My ego is more intimate to me, but not more certain than other egos
Source
Jean-Paul Sartre (Transcendence of the Ego [1937], p.104), quoted by Christine Daigle - Jean-Paul Sartre 2.1
Book Reference
Daigle,Christine: 'Jean-Paul Sartre' [Routledge 2010], p.23
A Reaction
Not sure how to assess this. Other people seem just as real as I do, when I encounter them, as friend or as foe. And in dealing with them we act as if dealing with their Self (rather than their legs, say). So this idea seems a good one.