Hi, I thought you may like this Mentalrobics exercise from Braingle.com:
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True or False

For each of the following statements, come up with two plausible reasons why they are true. Now, come up with two plausible reasons why they are false.

1. Candy is bad for you.
2. In a tennis match, the taller player will win more often.
3. Global warming can be reversed.

You can repeat this exercise by using any subjective statement that you can find. This exercise will help you to see that many issues have different sides to them.
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For more mind exercises: http://www.braingle.com/mind/