Disproving weak egoism seems pretty much impossible. However the extent to which you need to dilute egoism to make it intellectually air tight makes it, from a pragmatic perspective, worthless. I generally think that discussions of morality should have some pragmatic application.
These kinds of arguments, to me, feel like the arguments people bring in support of a rhetorical God. Congratulations, you have defined the universe and all the laws within it as being some kind of God. You still haven't differentiated yourself in anyway from atheists, except in your definition of God. The rhetorical account of god always seemed like a cop out for people who don't want to be ostracized for their lack of belief in a logical(e.g. unmoved mover), or active(e.g. biblical) representation of god.
These kinds of arguments, to me, feel like the arguments people bring in support of a rhetorical God. Congratulations, you have defined the universe and all the laws within it as being some kind of God. You still haven't differentiated yourself in anyway from atheists, except in your definition of God. The rhetorical account of god always seemed like a cop out for people who don't want to be ostracized for their lack of belief in a logical(e.g. unmoved mover), or active(e.g. biblical) representation of god.