Frege's puzzle about identity sentences has long challenged many philosophers to find a solution to it but also led other philosophers to object that the evidential datum it is grounded on is false. The present work is an elaboration of this second kind of reaction: it explains why Frege's puzzle seems to resist the traditional objection, giving voice to different and more elaborated presentations of the evidential datum, faithful to the spirit but not to the letter of Frege's puzzle. The (...) final outcome is negative, no satisfactory formulation of the evidential datum is found and Frege's puzzle is challenged until a better formulation of it is found. (shrink)