Christians sometimes ask themselves, "What would Jesus do?" In what could be thought of as a Jewish analogy to this question, Heschel challenges all Jews to ask themselves: would your Judaism be intelligible to Isaiah ? In other words, "What would the Hebrew prophets have you do?"
The Hebrew prophets teach us that, in analogy to God's limitless concern for us, there should be no limit to our concern for others.
This means that mitzvot should never be observed in isolation of concern for others.
Thus, even if I grant that avoiding contact with a member of the opposite sex is a mitzvah, it cannot be observed in isolation, i.e. it cannot be observed without considering how it causes others to feel.
We are approaching Yom Kippur. Consider what Isaiah has to say, in the haftarah for YK morning, about the mitzvah of fasting, if observed in isolation of concern for others:
58:5. Is this the fast I have chosen?
A day of self-affliction?
Bowing your head like a reed,
and covering yourself with sackcloth and ashes?
Is this what you call a fast,
a day acceptable to the Eternal?
6. Is not this the fast that I have chosen:
to unlock the shackles of injustice,
to loosen the ropes of the yoke,
to let the oppressed go free,
and to tear every yoke apart?
7. Surely it is to share your bread with the hungry,
and to bring the homeless poor into your house;
when you see the naked, to cover them,
never withdrawing yourself from your own kin.
8. Then shall your light break forth like the dawn,
and your healing shall quickly blossom;
your Righteous One will walk before you,
the glory of the Eternal will be your rear guard.
9. Then, when you call,(Translation by Chaim Stern.)
the Eternal will answer;
when you cry, God will say: Here I am.
Particularly resonant with the airplane issue is Isaiah's idea of "never withdrawing yourself from your own kin."
What would Isaiah have done, had he been on that plane?
1. The quote from Heschel I have in mind is the following, from "To Be a Jew: What Is It?" in Moral Grandeur and Spiritual Audacity, p. 9.
Our way of life must remain to some degree intelligible to Isaiah and Rabbi Yochanan ben Zakkai, to Maimonides and the Baal Shem.