In observant Jewish families, a child has the duty to ask four questions at the Passover Seder. ("Why is this night different from all other nights", etc.) "Four" is, in a way, a curious number. In the West, metaphysical baggage is usually associated with odd numbers, from one to nine (with twelve replacing eleven in importance). Yet "four" resonates in one way at least, for that happens to be the number of the fundamental and probably permanently unanswerable riddles of existence.
 Why is there something rather than nothing? This question is so basic that one has difficulty even grasping it. We cannot visualize "nothing." It is not a room without furniture or a vacuum tube or the vast spaces between the stars above or the atoms down here. Those entities are, or contain, something, but what does nothing look like or mean? And how is it even a theoretical option? Nor does the existence of the much used number "zero" help the visualization process.
 Having gotten that hot potato out of our hands, we turn to a more understandable but equally unanswerable puzzle: What is the design of the universe? There would seem to be only two choices: It is governed by chance, or it contains some ruling principle or divinity. (Unless there is an unlikely third, in-between option, one that involves a mixture of the two.) Religious people of course are heavily committed to the idea of coherence, of, as it were, cosmic law and order, but they differ noisily over who or what is the governor. Scientists, confining themselves to that corner of existence having to do with material, natural, physical matters, are at least able to come up with the laws of science. But those results, which intimate the existence of a limited ruling principle, come at the cost of ignoring the metaphysical, ethical, esthetic, humanitarian values which almost all people need for getting out of bed in the morning. Science cannot bridge the gap between "is" and "ought." Unable to tell us how to live, it leaves the idea of design amorphous.
There are, to be sure, thinkers who have tried to apply science to ethics and politics, but the very attempt means that they have stopped being scientists and become something else. Think, for example, of the dubious attempts to inject the idea of "survival of the fittest" into social and political arrangements. (Some ethicists subscribe to a natural law, but its existence is highly disputed.) A parallel question is whether this vast universe is all we've got or is merely, as some cutting edge scientists speculate, one of a series of multiple universes. Likewise part of the design puzzle are matters like what was in place before the Big Bang, what if anything is outside the universe, and is there an end to the whole thing or is the accelerated expansion of the universe--into what?--endless?
Design has to do with structure, architecture, setting. But design can also mean purpose, telos, goal. Hence a variant of the design question is, What is the meaning of life? The latter query obviously cannot be answered until one ascertains that there is in fact a structural design in play. If a personal God is part of the picture, then we have our marching orders, along with the attendant values. But if such a God cannot be found, the source of permanent, universal meaning becomes elusive, and such meaning as people find in a world of randomness is subjective, improvised, circumstantial, fictional, and temporary.
 Having quickly disposed of the cosmic riddles, we turn to humble earthly issues: How did inorganic matter turn into life? This one, unlike the first two, at least appears answerable--though holding one's breath until the answer comes is not recommended. Did lightning bolts act as catalysts of qualitative change? Is there some sort of potential leap in the, as it were, DNA of rocks and lakes?
 And then, in turn, how did living matter achieve consciousness? An ancillary question is, How did the limited consciousness apparent in animals and in some plants (e.g., perceiving the difference between day and night, winter and summer) turn into the active, voracious, shaping, consequential form of consciousness called intelligence or reason? Making us human, reason means finding patterns amid the infinity of facts--in effect, as it has come to be known colloquially in the wake of the 9/11 disaster, "connecting the dots." It means turning miscellaneous sensory experience into generalizations, generalizations that are useful and usable. It means, finally, taking the consciousness which we share with the animals and turning it into a creative force called "imagination"--the capacity to think of non-existing or impossible things like, say, utopia or travelling on a beam of light. And then doing something constructive or destructive with such thoughts.
When applied with determination, reason causes the bumbling, benighted caveman to develop, over time and through the accumulation of experience and memory, the Theory of Relativity, spaceships to the Moon and Mars, The Wealth of Nations, the American Republic, as well as, alas!, communist societies, Operation Barbarossa, Auschwitz. The power of reason explains why all the animals, many of whom are stronger or faster than homo sapiens, are behind bars in the zoo for our delectation rather than harassing us. Reason, in short, has a lot of good and bad to answer for, as the putative inferior animals cannot come up with an Aristotle or with extermination camps. So how did this powerful mental faculty, "reason," arise?
Other nagging questions there are aplenty, but they are either inessential or potentially answerable. If one of them should be deemed worthy of entry into this exclusive group of four, I stand ready to be persuaded to enlarge the list. Until then, these are the four questions that should be asked at a Seder--a modernized Seder that celebrates, or at least records, the appalling mystery that emanates from everything.