Trevize decides upon Gaia, and through mental adjustments, Gaia makes Branno and Gendibal believe they have won minor victories, and that Gaia does not exist. But Trevize is troubled by one final missing piece of information: in the course of their investigation, Trevize and Pelorat had found out that all references to Earth had been removed from the Galactic Library at Trantor. Trevize wants to know who did this and why, as Gaia denies having done that. He announces his intention to find Earth, since without knowing the answers to those questions, he cannot be certain his choice was the right one. Trevize also explains that he chose Gaia because that was the only choice of the three that was reversible in case his choice should prove to be wrong, due to the large length of time required for the formation of Galaxia.