This question branched off an earlier question. The earlier question was about the strength of a patent/patent application if the inventors later publicly doubt operability because data that was meant to demonstrate the desired outcome had been wrongly interpreted at the time of filing: Can a patent be invalidated when the inventors later publicly doubt operability and the reliability of reported results?
The above described situation brings forth another question:
If the operability of an invention is seriously in doubt (in this case by the inventors themselves), could this application still be considered prior art to a later application that actually solves the same problem demonstrably and unambiguously? The question is particularly relevant because some of the claims of both the earlier and the later application are broad and outcome-oriented (instead of method-centric). In both cases, the methods for the concrete main embodiment are somewhat different but the underlying physical mechanisms as well as the resulting, industrially useful effects are the same (except that in the earlier application it is not clear whether the effects actually occurred in the described manifestation or not).
Let me illustrate with a hypothetical example:
Let's assume radio communication has not been discovered yet. A scientist suggests that electromagnetic waves can carry information through the air. Of course this in and off itself is not patentable as it is a principle of nature. Now, an engineer develops a simple antenna, attempts to transmit a pulsed signal and records the result. The pulsed signal seems to appear in the recorded data and a patent is filed describing the antenna in the specs but also claiming in a broad claim a general method for electromagnetic communication. Later, the engineer notices that the recorded signals that were deemed to be the sent pulse train were actually more likely just noise from a malfunction of the receiver. Another engineer builds a better antenna (less noise) and also sends a more sophisticated signal that cannot easily be mistaken with noise (less ambiguity). She then files a patent application describing her embodiment and also including a broad claim for electromagnetic communication in general. In such a situation, can the patent office point to the similarity of the earlier claims as prior art (even though those claims were not supported by an operable invention)?
In the concrete case, the earlier application is currently in the national phase of the PCT process (not yet granted). The later application is about to be filed.