Escape from prison

[derrynoose]

A prisoner in a cell is being supervised by two guards, one of whom always tells the truth, the other of whom always tells lies. The cell has two unmarked doors, one leading to freedom, the other leading into a second cell.
The prisoner is allowed one chance to escape by asking the guard of his choice one question. When he gets an answer he can choose a door to open. What question will allow him to choose the door to freedom?

[andrea81]

Does his door open to freedom? (Oh gosh that doesn't make sense, but it's all I got!)

[Gizmonster]

Ask any guard, "if I ask the other guard which door is the door to freedom, which one will they indicate?" and then choose the other door.

Explanation:

If you ask this question to the liar, then the other guard would point out the correct door (as he is the truthful one), but the liar would lie and point you to the other door, so choosing the opposite of what the guard indicated would gain your freedom.
If you ask this question to the truthful guard, then the other guard would point to the wrong door (as he is the liar), the truthful guard would point you to the door that the liar indicated (which is the wrong door), so choosing the opposite of what the guard indicated would gain your freedom.

[derrynoose]

Thanks gizmonster. Excellently phrased explanation!

[issy]

Gizmaster's explanationis flawed.
If you ask the liar which door would the other guard recommend, he would point to the wrong door (the truthful guard would say the correct door)
If you ask the truthful guard he would also point to the wrong door (Which is what the liar would say).
Therefore, go through the door which the guard does not point to

[Gizmonster]

I don't see how my explanation is flawed:

Ask any guard, "if I ask the other guard which door is the door to freedom, which one will they indicate?" AND THEN CHOSE THE OTHER DOOR.

...... which is exactly the same as your answer !!