With discomfort, I share a link to a letter containing the Lub. Rebbe's criticism of TIDE.
I must touch upon another, and even more delicate, matter concerning the teachings of Rabbi Samson Raphael Hirsch whom you mentioned in your letter.
There has been a tendency lately to apply his approach in totality, here and now in the United States. While it is understandable that the direct descendants of Rabbi Hirsch or those who were brought up in that philosophy should want to disseminate his teachings, I must say emphatically that to apply his approach to the American scene will not serve the interests of Orthodoxy in America. With all due respect to his philosophy and approach, which were very forceful and effective in his time and in his milieu, Rabbi Hirsch wrote for an audience and youth which was brought up on philosophical studies, and which was permeated with all sorts of doctrines and schools of thought and disciplined in the art of intellectual research etc. Thus it was necessary to enter into long philosophical discussions to point out the fallacy of each and every thought and theory which is incompatible with the Torah and mitzvoth. There was no harm in using this approach, inasmuch as the harm had already been there, and if it could strengthen Jewish thought and practice, it was useful, and to that extent, effective.
We don't censor here, so if the Rebbe who is a towering figure, comments on TIDE, we'll share it.
I will add that Rav Hirsch's writings do not contain philosophic speculation. As he writes:
What is the use of torturing the youthful mind with “proofs” of the existence of God, with doctrines about the essence of God and His attributes, such as eternity, unity, incorporeality, with metaphysical speculations and demonstrations of why God must be eternal, indivisible and spiritual, and all the rest of what is called rational religion or rational theology? In reality, the maturest mind of a philosopher knows no more about the essence of God than the simple mind of a child; nor is it necessary for the moral behavior of man in this world to know more than the Torah tells us about God. It is not the longing for the world beyond which is the essence of Jewish piety; it is rather the joy of life, of active service of God, in our short or longer span of existence. To enlighten our mind לשם שמים for the sake of God, to ennoble our character for the sake of God, to acquire knowledge and the capacity to earn a living, to found a home and a family, to use all the material and spiritual means at our disposal for the noble and ennobling purpose of the great edifice of mankind which God wants to erect from the generation so the human family, לתקן עולם במלכות שדי—this is the aim, the striving for which make us into pious souls.
[Rabbi Samson Raphael Hirsch, “Education according to the Eight Psalm,” in Horeb, Introduction by translator, p. xlii.]
Also, the Rebbe might have confused what he saw at the U of Berlin with TIDE as done in Frankfurt, or maybe he was discussing TIDE as it might be applied in the USA as that would not have R Hirsch supervising it. Secular education at the Realschule was disciplined and practical. So there's Hirsch's TIDE and what would be the American version of it. And the Rebbe would be correct that you are not likely to get a Hirschian, Frankfurtian TIDE in the USA.
