The Yaavetz and Rav Hirsch

Yaavatz:

ואצלי דקדק באומרו: ודע מה ולא אמר ודע להשיב. כי אין ראוי
להתוכח עמו. ולזה אמר ודע מה שתשיב את האפיקורוס לא שתשיב
אם לא שתצטרך להשיב לקדש את ה' ברבים, אלא שתדע אתה
לעצמך שיהיה לבך חזק באמונתך ותשקוד על דלתי התורה יום יום.
I have noted that the Mishnah states: “Know what (you
would answer a heretic,)” rather than “know [so that you]
will answer (a heretic,)” for it is not proper to engage in
debate with him. That is why it states “Know what you
would answer a heretic,” i.e., not that you should
answer—unless you need to publicly glorify Hashem’s
name. Rather, you should know for yourself, so that your
faith is strong in your heart, and you continue to strive
daily at the gateway of Torah.

Rav Hirsch:

Finally, it would be most perverse and criminal of us to
seek to instill into our children a contempt, based on
ignorance and untruth, for everything that is not
specifically Jewish, for all other human arts and sciences, in
the belief that by inculcating our children with such a
negative attitude we could safeguard them from contacts
with the scholarly and scientific endeavors of the rest of
mankind. It is true, of course, that the results of secular
research and study will not always coincide with the truths
of Judaism, for the simple reason that they do not proceed
from the axiomatic premises of Jewish truth. But the
reality is that our children will move in circles influenced
and shaped by these results. Your children will come
within the radius of this secular human wisdom, whether it
be in the lecture halls of academia or in the pages of
literature. And if they discover that our own Sages, whose
teachings embody the truth, have taught us שנתן מחכמתו
לבשר ודם , that it is G-d Who has given of His own
wisdom to mortals, they will come to overrate secular
studies in the same measure in which they have been
taught to despise them.
You will then see that your simple-minded calculations
were just as criminal as they were perverse. Criminal,
because they enlisted the help of untruth supposedly in
order to protect the truth, and because you have thus
departed from the path upon which your own Sages have
preceded you and beckoned you to follow them. Perverse,
because by so doing you have achieved precisely the
opposite of what you wanted to accomplish. For now your
child, suspecting you of either deceit or lamentable
ignorance, will transfer the blame and the disgrace that
should rightly be placed only upon you and your conduct
to all the Jewish wisdom and knowledge, all the Jewish
education and training which he received under your
guidance. Your child will consequently begin to doubt all
of Judaism which (so, at least, it must seem to him from
your behavior) can exist only in the night and darkness of
ignorance and which must close its eyes and the minds of
its adherents to the light of all knowledge if it is not to
perish.

See, I am not advocating a retreat from the ideological principles Judaism holds dear. I advocate a robust Judaism able to tackle the challenges it faces in our time, just as it always has had defenders of the faith who stopped the breaches in faith and observance by having its leaders go and prove themselves the equals of the heads of the Academies of Athens, or of other sects of Judaism, of Christianity and Islam, and modern Atheism.

We do not need to hide behind fences, and indeed, we cannot.