He said A came up with the idea first, not that he implemented it first. You could have this timeline:
A comes up with the idea, starts working on implementing
B later, independently comes up with the idea, and start
working on implementing
B completes implementations, files for patent
A later completely implementation, files for patent
Under first to invent, A wins even though B implemented first. Under first to file, B wins.
> B could have seen A's idea and filed a patent on it
A could challenge B's patent on the grounds that B was not an inventor.
Thanks for your detailed response! If that's truly the case, then I could support this move to first-to-file.
One worry I have is that the order might often be more like:
A comes up with the idea, starts working on implementing
B later, independently comes up with the idea, and starts
working on implementing
B files patent application describing a grossly simplistic,
untested implementation of the idea
A later completes implementation, irons out the bugs,
files for a patent, starts a business, adds great value to
the economy
B never really does much with his patent, ends up selling
it off to C who sues A for mucho $$$ in patent licensing,
or sells it to A's competitor D for mucho $$$, so they can
copy A's product with impunity.
If that scenario actually happened, then either A's patent application would contain claims that are not in B's application (and in all likelihood, A's dependent claims would prevent B from completing their product), or A was just plain stupid about waiting too long to file or publish. (The other option is that B gets granted an overly-broad patent, but that's a completely different issue.)
Is this situation really better under the current law though? If you change the situation so that B had the idea first, but the rest of the facts are the same, then the current law produces the same problems.
The reason I suspect my situation is more common than the one you describe, if the first two lines are chronologically reversed, is that the time it takes A to go from idea to practical product and filed patent is assumed to be greater than the time it takes B to go from idea to filed patent, since B didn't wait until he had a marketable product before filing. This new system gives B a corresponding advantage over A.
Perhaps another assumption is that by the time the seeds for an idea are drifting in the ether, A would be more attuned to receive them, and would have started before B.
Though of course the situation you describe should be addressed, this change in policy may be an additional check against abuse that we are losing.
> B could have seen A's idea and filed a patent on it
A could challenge B's patent on the grounds that B was not an inventor.