Strive to find and point out what's right in any response.If this can't be done,probe to find out what prompted a student's thinking and dignify the student by validating it.If the student's perspective is different from what you have been promoting or looking for,simply point out that a lot of people share that perspective and ask the students,"How many of us know someone with a similar perspective?" Then continue to build from where the class left off before being diverted.