Much ink has been spilled and much discussion ensued in trying to analyze the difference between the question of the chacham and the rasha. On the basis of the question alone, there appears to be little reason to identify one as wicked and the other as wise.
When all is said and done, the line between good and evil is often very thin indeed. It is not easy to know how and why one child will use his wisdom for good and another for evil. Luckily—and tragically—some people cross this line many times over; the same person who does so much good can often do much evil, and those who do evil can also do good.
What is rarely analyzed and discussed is the difference between the chacham and the tam—this, for a seemingly good reason. One is bright, incisive and inquisitive. The other is simple, unsophisticated and aloof. This is especially true according to the Jerusalem Talmud, where the third of the four children is referred to not as the tam, but as the teepaish, the fool. While we cannot always distinguish good from bad, it is not too difficult to identify the wise and the simple.
Yet in a fascinating twist, the Jerusalem Talmud (Pesachim 10:4) inverts the answers given to the wise and simple—or, shall we say, foolish—child from that which appears in our Hagaddah. In this Talmudic version, the wise son is told, “with a strong hand, G-d took us out of Egypt” and the “foolish” son is the one who is told, “the laws of Pesach, we do not eat after the afikoman.” When one considers that it is the Torah itself that provides the answer of “a strong hand” to the question, “Ma zot, what is this?” asked by the third child, this version becomes most striking. Why would the Jerusalem Talmud take the answer meant for one child and give it to another?
Apparently, the Jerusalem Talmud wants to stress that sometimes, the same question and answer can be both simple and profound. “With a strong hand, G-d took us out of Egypt” may be a simple answer to a simple question. But at times, it is the answer to a more sophisticated question. The chacham wants to know about the various categories and nuances of mitzvot. He or she is looking for profundity. Sometimes we must tell him that such is not what is needed, or even desirable. We simply keep the mitzvot because G-d took us out of Egypt.
“And even this you shall tell him, like the laws of the pesach [sacrifice]: ‘We do not partake of dessert after the afikoman.’” The afikoman marks the end of the meal, alluding to the fact that the chacham must be taught everything from beginning to end. And we must then leave him hungry for more. The chacham understands that this law of not eating after the afikoman is k’hilchot hapesach and is modeled after, but is not the same as, the laws of the [korban] pesach. The pesach sacrifice, along with brit milah, were the two most important positive mitzvot, the only two for which the failure to observe them carries the punishment of karet, excision. The modern replacement for the korban pesach, the afikoman of today, is only an imitation. It is like—but is not—the paschal lamb, and must not be treated as such.
For the Jerusalem Talmud, this same answer is understood in a very simple manner. We don’t eat after dessert. That means one can’t go over to the home of friends after the seder and have a snack. It is in this context that the Jerusalem Talmud specifically mentions the prohibition of eating the paschal lamb at two homes. Pesach is the time the family eats a complete meal together. It is the strength of the family that has been the key to Jewish survival. Nice and simple.
Furthermore, at times the tam, unbeknownst even to himself, can turn out to be a chacham. Not because of sudden great expertise or some magical increase in intelligence, but because the simplest of questions at the right time can be the trigger to a much deeper understanding of the issue at hand. A novice with no training in a particular field can ask a simple question or make an innocent comment, totally oblivious to how such can transform an expert’s understanding of a most complex issue. Sometimes the tam sees what the expert cannot. Our Sages were serious when they noted that we learn the most from our students (Taanit 7a).
Upon reflection, it seems rather obvious that we all have qualities of each of the four children, perhaps even at the same time. And all four have their place. We need wisdom, but we need to know when we don’t even know what to ask. At times, we need simplicity and purity of faith, yet sometimes things are accomplished only by rebellion and breaking of communal norms. It is the truly wise who know which child they should be at any given time.
 With (thankfully) the Pesach seder so widely observed, many do not realize that the questions of the four children are direct quotes from the Torah. Actually, the Torah records three instances of a child asking his parents a question and a fourth where the parent initiates the conversation by saying, "You shall tell your child...” (Shemot 13:8), a reference to the one who does not know how to ask. As to why the authors of the Haggadah change the answers of the Torah for the chacham and the rasha, see here.
 Some don't even get excited if chatzot, midnight, is approaching and we are nowhere near ready for the afikoman. It can wait to be eaten, something we cannot say about the korban pesach.
 Fascinatingly, in the Jerusalem Talmud the "k", like", the laws is missing. Rather "you should teach him the laws of Pesach". This child is unable make distinctions between the different types of laws.