Why is "Why is the sky blue?" such a common question made by children? And why has that question about the question never been asked before?

Is it that the question is just a cultural artifact, that is, that someone remarked on one child somewhere actually asking that question once, and once written others pick up on the humor of such a deep philosophical question coming from someone so young, and then the humor being propagated through our current culture by the media?

Though many children do go through a 'why' stage, do most children go through this, if not verbally, at least psychologically? And is this cross-cultural?

As a side question, is the question "Why is the sky blue?" truly a question that can be answered by 'why'? Is it really asking for an event sequence description or is it misplacedly asking for a motivated causality (expecting of all events to be initiated by an actor)?

  • "Why is "Why is the sky blue?" such a common question made by children?" Is it? Or is that question just used as an illustration of the inquisitive mind of a child, the mind that asks plain questions about mundane things, comparing that to the adult mind that long since stopped reflecting over such mundane things.
    – MichaelK
    Aug 8, 2018 at 14:24
  • Note that, to help direct answers, there are multiple ways of answers the "why is the sky blue?" question: the physical manifestation of Raleigh scattering, atmosphere composition, and EM frequencies emitted by the sun along with biological properties of retinal receptors and neuronal processing, or the metaphysical one of whether a color perceived by one person is the same as that perceived by another, or an other number of possibilities. This question is about the sky/blue question and what it means to be a 'why' question (also maybe child psychology).
    – Mitch
    Aug 8, 2018 at 14:25
  • @MichaelK Didn't I ask refer to the question as a representative of inquisitiveness? But mundanity is surely relevant, and might appear in a more formal answer, but does that really answer my question?
    – Mitch
    Aug 8, 2018 at 14:34
  • No it does not answer the question. I challenged the question. Is it really true that children ask "Why is the sky blue?" a lot, or is it only said that this is what children do a lot?
    – MichaelK
    Aug 8, 2018 at 14:36
  • @MichaelK Do you think the idea of mundanity as you get older is a central part of the situation? Could you put that in an answer?
    – Mitch
    Aug 8, 2018 at 14:53

4 Answers 4


The sky being blue is something that we can all observe daily, but which does not seem to have a clear impact on our lives. So it's something that most adults have learned to take for granted and not question. Children, however, have a tendency to notice things that adults don't, and to ask questions about them. So "why is the sky blue?" is a plausible question for a child to ask.

Although modern science does have some explanations for this, it still stands as a paradigmatic example of a very familiar phenomenon for which most adults neither know nor seek an explanation.

As such, it's also a good stand-in for a philosophical inquiry, since many of those revolve around questioning familiar phenomena or assumptions that the majority of people take for granted.

  • Hm... like kids, seeing things new (or realizing them) for the first time, where we've all been habituated to them and don't notice, makes them more skeptical than those with more experience?
    – Mitch
    Aug 8, 2018 at 19:34

As someone whose professional life revolved around science, I see this as a scientific question which is asking for an event sequence description. If I were a philosopher, I might think it was philosophical.

At least one of my kids asked that*, so it must not be a rarity (though that conclusion doesn't necessarily follow.)

*I remember having to look up the answer.

I think your question is a false dilemma, btw. Many young children ask questions simply for attention, to try to make a point, to hear themselves speak, etc. But that's the parent in me speaking. Answering in a realm outside of my common experience is difficult.

  • This is my first thought, what about the light is making it blue (because sometimes, it is red like toward evening). And then maybe it's something about the processing of the eye and brain. But then I think maybe other people see green and I see green when they see blue (and it then becomes a question of philosophy about if color is a property of an object or of the eye or what). Or maybe it is about labeling or the arbitrariness of things. So I think there are lots of possible good answers.
    – Mitch
    Aug 8, 2018 at 19:29
  • Also, there's a question about the purpose of language. Is it a coding mechanism to actually transfer information (like a mechanical description of biological pathways) or is it a social construct, to elicit a call and response pattern to augment in-group strength, or is it, like dreams, just mental processes being repeated in order to strengthen internal connections?
    – Mitch
    Aug 8, 2018 at 19:32
  • I agree that labeling is a problem neurophysiologically. I can't see language as facilitation without purpose, though. It is believed by neurophysiologists (based on histopathology) that the most common form of schizophrenia is due to the lack of synaptic pruning (in effect, errant pathways are facilitated as well as correct ones.) But language may be a problem here between us. Aug 8, 2018 at 19:48
  • As far as dreams go, I have no real understanding of them, so I can't say one way or another. I have my hypotheses, and I can find research that supports my hypotheses, but I know that that's just supporting my own bias. Aug 8, 2018 at 19:52
  • If I think I understand what you mean by 'facilitation without purpose', there are lots of behaviors that are simply fashion, and many parts of language, because it is so arbitrary and non-representational, is fashionable/purposeless/artifice. Why do most shirt collars have that particular angle? Oh, many years ago most had another. Why do people in the US say elevator and not lift? Same reason (which is no reason at all just a description, which frankly was the motivation that got me to ask here, all the ELU questions about 'Why? Why? Why?' when it just is, there's no cause.
    – Mitch
    Aug 8, 2018 at 20:21

The English word "why" has several meanings, thus the question is ambiguous. Aristotle, for example, recognized four kinds of causation. What he would have called the "material" cause is Rayleigh scattering--the different bending of different colors of light in the atmosphere. There might be other material causes from different perspectives; for example, light of blue wavelengths stimulates receptors in the retina differently, and the brain interprets these in a certain way.

If the question is about agentive cause (i.e., "for what purpose"), then we must pre-suppose an agent--whose purpose? Or we might duck the need for an agent with an evolutionary explanation: we evolved a sense of sight with color perception that helped us distinguish the salient features of our world.

Children do indeed like to ask "why". They should be taught to be more specific. :-)

  • Nice. Four causes. Also, there is the concept of Five why's which while not supposedly philosophical, does seem to be more reminiscent of the child's motivation (or at least the way adults tend to take it), which seem to hit any one of Aristotle's categories based on which verb was used in the previous answer to the child. Also, there is the problem of justification, which brings up the proof trilemma, circular, infinite, or axiomatic patterns.
    – Mitch
    Aug 8, 2018 at 19:17
  • As to asking kids to be more specific, you'd think asking a question back would stop them, but no, they're better than that. "Dad, why is the sky blue?", "Well, do you mean operationally, or what purpose, or some other?" "Dad, why are you so defensive? Do you just not know?"
    – Mitch
    Aug 8, 2018 at 19:22

Who's on first. What's on second. I don't know is on third.

Above and beyond the ambiguity of language there is the ambiguity of human thought, even in a single individual. Put two humans in a room and have them talk and they will inevitably misunderstand both each other and themselves.

The question can be either, depending upon context, intent, cultural indoctrination, etc. In the most literal interpretation, I would argue that the nature of the question depends mainly upon what information the individual asking the question is seeking.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .