How to avoid ambiguity in the question: "Why do you think...?"

Let us say I want to know why the sky is blue, my understanding is that I can ask you: "Why do you think the sky is blue?" regardless of whether you have thought about it before or not. It seems from the moment you hear this question you start thinking about it. Here the emphasis is really on the natural phenomenon, not on the person who is thinking about it.

On the other hand, let us say my friend told me he thinks that life exists on Mars. Then I can also ask "Why do you think life exists on Mars?" It seems to me that these two situations are different. The emphasis here is on the person, on what lead this particular person to think in a certain way.

Are there ways to slightly modify either or both questions so as to indicate the difference between these two situations?

Why do you think the sky is blue?

Depending on context, the above question could have an almost whimsical feel to it. The questioner might not really be concerned with finding an answer, perhaps he or she is merely saying out loud a thought which struck them at that moment. If the person asking wanted a scientific explanation then a more appropriate question would be: "Why is the sky blue?" The sky is blue (or it appears to be so) is a given fact, it is not an opinion. The reason for it being blue is the question being asked.

Why do you think that life exists on Mars?

There is a slight ambiguity in the question. Does the questioner also think there is life on Mars? Or is he or she challenging that person to justify their conviction, opinion or belief that there is life on Mars today? Not everyone upholds the opinion that there is life on that planet, many believe that some form of life may have existed in the past and some are convinced that there has never been any life on Mars. In any case, the question is clearly asking for clarification.

Alternative phrases are the following:

PRESENT EVENT

• Why is there life on Mars? [fact]
• Why do you think there is life on Mars? [opinion]
• Why do you think life exists on Mars? [opinion]
• Why do you believe that life exists on Mars?
• Why are you convinced life exists on Mars?
• What makes you so certain that life exists on Mars?
• What proof do you have that life exists on Mars?

PAST EVENT

• Why was there life on Mars? [fact]
• Why do you think there was life on Mars? [opinion]
• Why do you think life existed on Mars? [opinion]
• Why do you believe that life existed on Mars (etc.)

I have the same issue and question.

For example, I am pretty annoyed with questions being phrased as "Did you know that ... ?"

For example,

• Did you know that the range and variation the life span of a humpback whale is the same as humans?
• Did you know that the white-tail (aka white tailed) deer is native to northern and central Americas?

Why can't people simply ask "Do you know ... ?" ?

Because "did you know ...?" implies that you may know now, but did you know before I asked you?

Therefore,

• "Why do you think ... ?" is to ask a question to imply present thinking.
• "Why did you think ... ?" is to ask a question to imply past thinking.
• "Why would you think ... ?" is the non-finite way to ask a question to cover past, present and future bases.
• "Why should you think ... ?" is a more assertive questioning in non-finite time.
• "Why might you think ... ?" is to ask a question to imply your thoughts are unknown, but there might be a possibility that you think that way.

This mode of questioning is a way to focus on questioning the opinion, without accusing or implying the other party whether it is their past, present of future opinion, except that it is quite apparent that he/she does have that opinion.

Why would you think that there is life on Mars?

To me, avoiding ambiguity in this case just requires you to use the word causes.

For example:

Why do you think the sky is blue?

What do you think causes the sky to be blue?

And

Why do you think that life exists on Mars?

What causes you to think that life exists on Mars?