I’m not sure I’m following your point. So, omniscience, to know all things knowable, is not possible?
There are some things that are regarded as common or shared knowledge, such as who won the battle of Hastings or that water starts expanding at 4 degrees C before it freezes at 0 degrees. there are other things that could be known by someone but which aren't such as the number of paving stones I walk over on my journey from the station to the school. Would you say that I was
more knowledgeable for actually counting them? I guess that most people would not because they assume that when you talk of how much you know, they are implicitly comparing you with other people so it only makes sense to compare knowledge of commonly known things. There again, most people would not consider all the thoughts that one has as entering into that pool of knowledge even though these thoughts use common language. There are many non-verbal thoughts too such as feelings and emotions.
I'm thinking of the Bible here - and common sense. As you can see, there are so many assumptions that are being made, often completely unknown to the person making the statement. I doubt that most people when they say that God is omniscient have a clear concept of the kind of knowledge they are talking about. And I would bet that even if they did, they would be wrong. Because people tend to think that the most intelligent beings are like them only faster or more extensive. The Bible scotches this idea when it says that to God a day is as a thousand years and a thousand years as a day. It's about perspective. This statement says at the same time that God is interested in many more details than we are interested in
and that he is much less interested in the details that we are interested in and more interested in the bigger picture. We would say in modern terms that he has a 'different agenda' to what we have.
So here's a synopsis of the position:
1. The term omniscient, as used in 'God is omniscient' frequently implies a comparison with the knowledge possessed by human beings. God is portrayed in effect as a superhuman. Since God has a different agenda to us, the comparison is worthless.
2. Although the assumptions in the statement are often vague, there is one that is probably most often present and that is that God can and does read the minds of everyone and is privy to every thought. I honestly don't see this is in the Bible at all. Perhaps an example of the agenda issue. In the Bible I find that God is an excellent judge of character and motive but not a mind reader.
3. Because the assumptions in the statement are vague, I don't see why I should have to comment on it as if it were a matter of doctrinal importance. If terms were better defined, I might be more sympathetic but 'All that is possible to know' sounds like a cop out', sound bites.
'Now I know that you fear God' is a text I discussed at length with Lon in the 1-on-1. Feel free to have a look. I also mentioned the incident when God came down to visit Sodom to find out what it was like there. I really don't think it is necessary to suggest (and even less to be dogmatic about it) that God needs to know 'everything there is to know' in order for him to be God.