"To be" assumes that 1) it is possible to extract the information non-destructively, and 2) that it is possible to extract the information at all. The closer the measurement, the more you measure the interaction between the measuring instrument and the observed phenomenon, rather than the phenomenon itself.

Regarding the Ship of Theseus, our identity is most likely tied to an ever evolving process that depends on the architecture of our brains rather than a fixed set of molecular components. Beside the neuronal DNA, most if not all cell components are subject to a turnover.