In the Passover Haggadah there is a parable about four sons, the wise, the wicked, the simple, and the one who does not know what to ask.
According to one explanation, this parable refers, historically, to four Jewish generations.
The first generation was wise, deeply immersed in Jewish culture and religion.
Then came the generation of rebellion, which we call—though perhaps you won't accept it—wicked.
The third generation is really not wicked.
It does not rebel against Jewishness—because it knows so little about it.
However, when the member of the third generation comes to his grandfather for the Passover Seder, he sees many strange things and he asks about them.
He has something to ask about.
Now, the real problem comes with the fourth generation.
The son of the fourth generation—where will he come, what will he see?
Because he will not see anything Jewish at his grandfather's.
He will not even be able to ask questions.
The tragedy is that this story is about all of Jewish life in many ways.
If things continue the way they are, there will be a need not only for a memorial foundation for the Jews who were killed in the Holocaust, but also for a greater memorial foundation for the Jews whom we lose through assimilation.
–Rabbi Adin Steinsaltz
From On Being Free by Rabbi Adin Steinsaltz