Kt Templar
Well-Known Member
Cos the sonic is like the Doctor's smartphone, and he syncs it with the Tardis console every time he goes back inside, thereby backing-up. All he had to do for a new Sonic was restore his operating system from the most recent backup.
Or it's kinda wifi attached to the TARDIS and the computing info is shared.
Course that would mean that the Doc should be able to summon the TARDIS with the sonic if he wanted to... seems that he, or the writers more likely have forgotten or deliberately not done that as it would close off a lot of dramatic avenues.
So wifi shared computing but only when he is very close to, or inside the TARDIS itself.
Pure speculation of course!