There was until yesterday in this forum a thread which started as a discussion about the use of genitive in Ephesians 4.9. Soon discussion deviated to general issues of studying. The starter of the thread deleted all of his posts, so that I had no other choice than to delete the thread.
I still can't understand his reaction to things that I consider trivial. It seems that they are not, at least not to all of us, which is the reason of this post, in case other people too might find some help - or some anger!
In studying Greek or anything there are no Authorities. This doesn't mean, obviously, that we all have the same knowledge. We don't. But no one, no matter how great his knowledge might be, no one is an Infallible or Omniscient person. Knowledge changes, even scientific knowledge can change and has changed in the course of time dramatically. Therefore, all opinions are potentially wrong or insufficient and can/should be under examination. The King in studying is Arguments, not the supposed authorities.
Especially in studying Greek and in similar cases, this examination is a task open to anyone, since common reasoning is the principal power that underlies this kind of studying.
Most of the authors of grammar books are persons of (in the best case) limited philosophical abilities. We learn about Greek from a few paragraphs of Heidegger much more (more interesting and crucial) than all the wisdom we can get from the best authors of Greek grammars.
The grammarians' want of philosophical thinking leads them even to absurd conclusions, as is the case with some of them mentioned in the deleted thread, who fail to recognise even the most obvious, that there exists a sense of possession in the so called genitives of the whole or partitive genitives.
These are considered by them to be opposite to possessive genitives, although even a small child can understand that a whole possesses its parts and the parts belong and are subjected to the whole.
A part of the earth is a part because the earth needs it and owns it, or rather it is first a part and then the earth starts to own it?
A part of the earth can not even exist without the earth, just as a member of a body can not be alive without the body. Therefore the possessive sense is more important than the partitive sense, so that, even if the inventors of the partitive sense as opposite to the possessive, were only trying to arrive to a more primary and important definition, even without denying the possessive sense, they would be wrong, since the possessive sense is more primary and important than the partitive sense.
Here is how one can understand a grammatical issue, without having an Oxford degree in grammar, just by exercising man's reasoning power, avoiding to be seduced by the sirens of diplomas and authorities. As Plato, who had no university degree, and to whom our universities and the whole of the Western thinking is based, consults, we'd better not ask where a man is from, but just examine if what he says is right or wrong.
Thinking is the difficult and also the interesting task in studying. It is easy and boring to follow authorities, and it is even dangerous, because this enslavement tends to expand to the whole life and creates persons without power to discern false from true, always subject to fanaticism, always waiting to just listen and follow the supposed authorities' commands.
Thus, my advice would be for all of us to remember Plato's advice. No matter if someone is young or old, Greek or barbarian, man or woman, Ph.D owner or self-taught..., just listen to what he says and judge the arguments - not the age, or the color, nationality, diplomas, etc.