I've talked before about how I much prefer to focus on what my PCs will do in my games rather than can they do something. For me it is more interesting, and is a question that comes with built in drama and intrigue while can is just a yes/no question. However, a lot of RPGs and adventures focus on can. And there is no problem with having "can" in the cards. Today I want to talk about what the three questions reveal about characters, and also when you should be looking to ask them.
Can This Be Done?
Can is the least interesting of the questions, but it is also the most common. Any time you bring out the dice with a difficulty associated for a task you are asking "Can the PC do this?" and everytime they succeed the answer is "Yes" and everytime they fail the answer is "No" and that is about the whole of it.
Being over focused on the question "Can" is what gets GMs into trouble with things like thinking their PCs are getting too strong too fast, or have been given too many magical items. If you find yourself concerned you have no way to challenge your PCs in combat, you are asking the Can question.
And like I said, there's nothing wrong with this question. Most bought modules and pre-packaged campaigns are focused on this question. I mean, the very presence of an end boss or 'final fight' in your game is a Can question. So don't fret if you're using it. Just be aware of what you're doing.
Will This Be Done?
The Will question is also the What question. Basically "Will a character do this?" or "What will the character do?" Will, like Can, is a yes/no question, but it also - in my opinion - is a stronger question because it reveals something about the character in question.
Consider: Can the Paladin save the princess? vs. Will the Paladin save the princess? With the first question we get a standard D&D plotline of a damsel in distress and a hero going to save them. With the second, well, there's a lot more going on now isn't there? I mean, why wouldn't the Paladin want to save the princess? Why is this a question? Who is this Paladin? Who is this Princess? And in the answering of the question we learn more about the Paladin too. Maybe they're not the type of Paladin that saves princesses, but what does that mean?
How Is This Done?
How is a question you should ask your players. Sam says he attacks, but how does he attack? Maybe Sam isn't feeling very creative and he says with a sword. That's fine. However, with the prompting maybe Sam tells you he takes his great sword in both hands and charges forward before delivering a powerful overhead chop. Well, hey now, now we're getting somewhere.
How things are done - how things are described - can be huge in differentiating two characters. Consider two fighters, one who pushes in brashly and delivers wide, sweeping swings of the sword, and another who makes cautious, probing thrusts with a spear while waiting for the right moment to unload. You get different impressions of who these characters are as people, and that can be very important for making sure two players don't feel they're constantly stepping on each other's toes.
When To Ask The Questions
In my opinion, as the PCs get stronger - and more defined by their players - you should focus less and less on "Can" questions and more on "Will" or "What" questions. That isn't to say that you don't ask Will/What earlier on - that's an important thing to help players develop their PCs - just when the PCs are lower level and lower power it is more interesting to ask the Can question.
Can this plucky band of nobodies defeat a dragon? Can they save the kingdom? Can these rookie pilots take out all these TIE fighters? Can they negotiate a truce between the Lion and Crane clans?
However, as the characters show they are potent and capable, that they can do these things, then Can becomes less interesting. I mean, Can the band of dragonslayers kill a dragon? I mean, probably, they're professional dragon slayers. However, will they? And how? Now those are characters that can add a lot of meaning to the story and help flesh out both the world and the characters within it.
So consider all three questions when planning for your game. You'll find things work a little smoother, and may be surprised by what you reveal about your characters.