Post Modernism and Jewish Legitimacy

There seem to be a lot of arguments, especially within Orthodox circles, regarding what is and isn't a "legitimate" Torah opinion. I find myself increasingly perplexed in face of these discussions. In a social reality where everyone chooses for themselves what, how, when to do things and the concept of identity so individualized and fluid, what relevance does the term 'legitimate' even have any more with regard to religious belief and practice (other than societal association)?
You may say - the discussion is "what is Halachically legitimate". Here too, the variety of opinions on so many major issue are so great that - (and this is a key element in this argument) without a Sanhedrin or other centralized Halachik authority - the term seems to loose its meaning.
There are attempts to draw general lines between those who are "out" and those who are "in" but that, too, is an illusion - depending on who you ask, the border of the consensus shifts drastically.
If Rav Nachman said that people who learn Guide to the Perplexed "have an image of idol worship on their face", Rav Elchanan Vaserman said that Religous Zionism is "joint idol worship" (עבודה זרה בשיתוף), Rav Shach called Chabbad a "cult similar to Judaism" and in return was identified as a force of 'The Other Side' (סיטרא אחרא) and let's not even start on what some rabbis - through the ages - said about Kabbala, I find it futile to speak of a consensus.
Even Rambam's 13 principles of faith have been disputed and interpreted to such extent that make them mute as a binding creed and the Shulchan Aruch expounded upon to the point that we no longer have (if we ever did) a unifying code of normative practice.

One can argue for or against this reality but it does little good to act as if there is still such a thing as "THE Halacha" or "THE Jewish opinion".
Even if many Torah Jews (think they) have escaped post modernism, Torah and Judaism have not. (250+90)

Torah Awaits a Revival

Torah should be what propel the State of Israel forward in social and cultural matters (in the wide sense of those terms) and not just cause us to man the barricades of the Shulchan Aruch to preserve the status quo. Is there anyone who has a clue how to run a modern economy according to the Torah? is there anyone who even has a suggestion for it? is there anyone capable of imagining what "Jewish" foreign relations look like in a global village? So, are we doomed to wait for a prophet and until then we should just hold down the fort dreaming of the return of the good old days? Although we're doing the best we can in translating the language we know into a new reality, we need someone from the outside to expand the language we're using, or better yet, just start speaking it and we will have to follow suit. For instance – if the Knesset were to legislate that all immigrants who live in the country for 10 years, serve in the army and identify with core values of Judaism are considered Jewish for the purposes of marriage, burial, etc… Halacha would eventually find a way to except it – without breaching Halacha, as it would already be a reality.

To what is this analogous?
When Eliezer Ben Yehudah revived the Hebrew language he used as much of what he could from Jewish sources but, obviously, it wasn't nearly sufficient. The Hebrew of the sources just wasn't rich enough to relate to the realities of modern times. Out of his familiarity with the new realities he tried to fit them into constructs that may have already existed but the result included many completely brand new words.

The Torah awaits its revival, too.

Why am I Observant?

I don't feel like I have to, I'm not afraid of what will happen to me if I don't, it's not because my soul was commanded at Har Sinai (maybe it's just me but I have no personal memory of the event, just a communal one) and it's not because it makes more sense than other faiths (which it may or may not).
It's because I choose to be part of the historical phenomena called - The Jewish People. Call me naive, but I have come to Trust The System (or, TTS as I've come to call it). The miraculous system that has sustained thousands of years, with all its ups and downs, molding and creating a better society and a better world; a world with moral absolutes, a world that abhors violence and cherishes kindness, a world of rules and laws that strive for morality and aspire to the divine. That is the kind of system I choose to be part of to the extent of my ability. Sometimes I do a better job at participating and contributing to this endless process and sometimes not as much but, why am I observant – because I choose to be part of the most significant system I know of.(207)

People don't follow Halacha because of God

Ask any 3 observant people what they mean when they say "God" and you'll get 3 different answers. Even so, they're all leading observant lives. This leads me to understand that it is not theology that causes people to follow Halacha. All theology – Jewish, non Jewish, different streams within Judaism – can be understood and logically defended. Meaning, it is something else that causes people to follow Halacha and that is that they choose to take upon themselves a certain way of life for all kinds of reasons: they want to be part of a generational continuum, it fills their lives with direction, it's what they're familiar with, they don't want to get smote by lightning, they want to be told what to do, they want to be part of a community, or whatever. The important thing in this idea is that it is all a choice. That becomes even truer in today's day and age when people have the ability to choose what they want, when they want, how they want with little consequence other than the choice itself. And all these myriad of choices make up the phenomena which is The Jewish People which seems to be the point of it all. The only question is – to what degree do I choose to participate and take part. (218)