I Liq Chuan Diagram - Mechanism of Body Movement

Kalama Sutta (Kalama Sutra)

Do not simply believe what you hear just because you have heard it for a long time.
Do not follow tradition blindly merely because it has been practiced that way for many generations.
Do not be quick to listen to rumors.
Do not confirm anything just because it agrees with your scriptures.
Do not foolishly make assumptions.
Do not abruptly draw conclusions by what you see and hear.
Do not be fooled by outward appearances.
Do not hold on tightly to any view or idea just because you are comfortable with it.
Do not accept as fact anything that you yourself find to be illogical.
Do not be convinced of anything out of respect and deference to your spiritual teachers.

You should go beyond opinion and belief. You can rightly reject anything which when accepted, practiced and perfected leads to more aversion, more craving and more delusion. They are not beneficial and are to be avoided. Conversely, you can rightly accept anything which when accepted and practiced leads to unconditional love, contentment and wisdom. These things allow you time and space to develop a happy and peaceful mind. This should be your criteria on what is and what is not the truth; on what should be and what should not be the spiritual practice.

-The Buddha

wikipedia entry