Haredim have turned belief in the Ari's system of Kabbala into a litmus test for membership in Orthodoxy. This is a shame for many reasons, not the least of which is the misunderstanding of the Ari's place in history inherent in that litmus test.
The Ari lived during the Renaissance, a time of intellectual enlightenment and rationalism. Universities were springing up throughout Europe, and Humanist culture was king.
Judaism had a long tradition of what was then viewed as irrational thought – worlds created and destroyed before this one, 974 generations of men who lived before Adam and the idea that this world was very much older than 5500 years. These propositions were very alien to European and Muslim thought, whose rationalist tendencies were filtered through literal reading of Scripture. Midrashim that spoke of generations before Adam were viewed – and derided – as fairy tales.
The Ari took these midrashim, aggadot and kabbalistic works and rewrote them. He – without Jewish sources to base himself on – turned the 974 physical generations that lived before Adam into spiritual generations that existed only in God's thought, not in the physical world. In doing so he rectified so-called "primitive'" aspects of Judaism with Renaissance thought. This change was very appealing to young intellectuals, many of whom joined the Ari's circle or the circles that later formed around his disciples. Because it did not involve changing any practical Halakha or abrogating the midrashim and aggadot in question – after all, the Ari's system was simply hashgafic thought, a philosophy of creation, if you will – there was no reason to oppose the Ari's new views. The Ari's new system, a hybrid of mysticism and Renaissance rationalism, took hold.
Fast forward to the Rabbi Nosson Sifkin ban. 'Gedoloim' like Rabbis Elyashiv, Wachtofel, Shapiro and Feldman now mandate belief in the Ari's system even though today's rationalist thought backed up by reams of empirical scientific evidence now knows that the world is in fact billions of years old.
If the Ari were alive today, it is highly unlikely he would construct a system that mandates belief in a 6000 year old world. If anything, he would trumpet the teachings of Yitzhak mi Akko. But today's 'gedolim' know nothing of history, nothing of theology, nothing of pre-Ari kabbala and nothing of science. They are small men in the worst sense of the word, and they are destroying Judaism. Some, like Rabbis Elyashiv and Wachtofel, are truly evil men. Others are simply pious fools. A few, like Rabbi Aharon Feldman, really should know better.
The 'gedolim' have drawn a line in the sand and dared us to cross.
For the sake of our future generations, for the sake of Judaism itself, we must take that dare.
Truth is more important than dogma.