Socrates was one of the greatest educators who taught by asking questions and thus drawing out (as 'ex duco', meaning to 'lead out', which is the root of 'education') answers from his pupils. Rather stupidly, he martyred himself by drinking hemlock rather than compromise his principles. Bold, but not a good survival strategy. But then he lived very frugally and was known for his eccentricity. His pupils, by the way, include Plato and Aristotle. Plato wrote up much what we know of him.
Here are the six types of questions that Socrates asked his pupils. Probably often to their initial annoyance but more often to their ultimate delight. He was a man of remarkable integrity and his story makes for marvelous reading.
The overall purpose, by the way, is to challenge accuracy and completeness of thinking in a way that acts to move people towards their ultimate goal. Don't waste time by doing it for your own gratification. Get your kicks vicariously, from the movement you create.
Conceptual clarification questions
Get them to think more about what exactly they are asking or thinking about. Prove the concepts behind their argument. Basic 'tell me more' questions that get them to go deeper.
Why are you saying that?
What exactly does this mean?
How does this relate to what we have been talking about?
What is the nature of ...?
What do we already know about this?
Can you give me an example?
Are you saying ... or ... ?
Can you rephrase that, please?
Probing of assumptions makes them think about the presuppositions and unquestioned beliefs on which they are founding their argument. This is shaking the bedrock and should get them really going!
What else could we assume?
You seem to be assuming ... ?
How did you choose those assumptions?
Please explain why/how ... ?
How can you verify or disprove that assumption?
What would happen if ... ?
Do you agree or disagree with ... ?
Probing rationale, reasons and evidence
When they give a rationale for their arguments, dig into that reasoning rather than assuming it is a given. People often use un-thought-through or weakly understood supports for their arguments.
Why is that happening?
How do you know this?
Show me ... ?
Can you give me an example of that?
What do you think causes ... ?
What is the nature of this?
Are these reasons good enough?
Would it stand up in court?
How might it be refuted?
How can I be sure of what you are saying?
Why is ... happening?
Why? (keep asking it -- you'll never get past a few times)
What evidence is there to support what you are saying?
On what authority are you basing your argument?
Questioning viewpoints and perspectives
Most arguments are given from a particular position. So attack the position. Show that there are other, equally valid, viewpoints.
Another way of looking at this is ..., does this seem reasonable?
What alternative ways of looking at this are there?
Why it is ... necessary?
Who benefits from this?
What is the difference between... and...?
Why is it better than ...?
What are the strengths and weaknesses of...?
How are ... and ... similar?
What would ... say about it?
What if you compared ... and ... ?
How could you look another way at this?
Probe implications and consequences
The argument that they give may have logical implications that can be forecast. Do these make sense? Are they desirable?
Then what would happen?
What are the consequences of that assumption?
How could ... be used to ... ?
What are the implications of ... ?
How does ... affect ... ?
How does ... fit with what we learned before?
Why is ... important?
What is the best ... ? Why?
Questions about the question
And you can also get reflexive about the whole thing, turning the question in on itself. Use their attack against themselves. Bounce the ball back into their court. Etc.
What was the point of asking that question?
Why do you think I asked this question?
What does that mean?
The only magic is perseverance