I was making the point that based on the fact that it's been "almost 100 years [that] have passed since 1914, we now know that Jesus could not have had in mind a 20- or 23-year generation, so we can now infer that Jesus was referring to a period of time as a 'generation.'"
Or the simplier answer would be that since generation is such an easily understood word, then perhaps the 1914 date is the incorrect starting point and not this inaccurate definition of the word generation? Nah, because if that happened, the GB would be in the position of having to pick a new time for the last days to start and that would be much harder to pull off than what they came up with. What a second, haven't they done that before? Why yes, I believe 1874 was the first WTS date that was to be the beginning of the last days.
Your example about the definition of planets isn't a good comparison. Since when does the IAU order people shunned because they don't believe in their definition of planet? For that matter, when did the IAU claim to be spirit directed?
Didn't the WTS greive the holy spirit when they originally defined the generation as the ones who saw 1914, then changed it to the wicked living in the last days, then changed it to the annointed in the last days? I would think that Holy Spirit would have guided them correctly at least one of these times? Why would they be directed to proclaim something that wasn't accurate?