We can consider the rasha, the evil child, to be a failed chakham (the wise one). He is engaged with the laws of Pesach, but unlike the first child, he rejects them.
The third son, the tam, is usually defined simple in an unsophisticated or ignorant sense, as though his approach is inferior to the wise child’s. But when we find the word “tam” in the Torah, it is a complement. Yaaqov grows up to be an “ish tam yosheiv ohalim — a tam man, who dwelled in tents”. There is a kind of simplicity that is holy, positive — being of one mind, pursuing G-d without conflicting desires or motives.
And if the tam is someone who pursues Hashem on an experiential, desire, level, then the she’eino yode’ah lish’ol, the child who doesn’t even know to ask a question, is his failed counterpart. Just as the rasha is one who tries to encounter Judaism on the chakham‘s cerebral level but rejects what he finds, the she’eino yode’iah lish’ol fails on the experiential level, he finds nothing he can relate to.
And so we continue the Hagadah explaining why the mitzvah of retelling the story of the Exodus is limited to the night of the seder:
יָכוֹל מֵרֹאשׁ חֹדֶשׁ, תַּלְמוּד לוֹמַר בַּיוֹם הַהוּא, אִי בַּיוֹם הַהוּא יָכוֹל מִבְּעוֹד יוֹם, תַּלְמוּד לוֹמַר בַּעֲבוּר זֶה – בַּעֲבוּר זֶה לֹא אָמַרְתִּי אֶלָא בְּשָׁעָה שֶׁיֵשׁ מַצָה וּמָרוֹר מֻנָּחִים לְפָנֶיךָ.
I might have thought [the mitzvah applies] from the beginning of the month. Therefore we learn from what [the Torah] says, “on this day”. If it’s “on that day”, perhaps the mitzvah begins while it’s still daytime. Therefore we learn from what it says, “because of this” [– “this”, indicating something to point to]. “Because of this” I wouldn’t have said except at a time when matzah and maror are set out before you.
The mitzvah of telling the story cannot be cerebral teaching, from a book. It must be accompanied with the mitzvos of matzah and maror. An experiential education, an inculcation. This is the only way to reach the disaffected, the she’eino yode’a lish’ol.
And even the rasha requires this approach. The thing that gets someone to reconsider their postulates and explore a different philosophy is the experience of (eg) a Shabbos or a Pesach seder. Otherwise, all the “proofs” in the world fall on deaf ears.