It is wise from time to time to contemplate the things you think are certain, for example, “The sky is blue. The ground is stable. Life is short. I am alive.” Then ask yourself if there is any way that these certainties could be an illusion.

What is an illusion? Generally speaking, an illusion is something perceived or interpreted by the senses that is wrong or deceptive, a figment of the imagination. “Appearance” is another way of describing an illusion. Identifying illusion is easy if you have already determined that what you perceive is false, a hallucination, or has arisen from your imagination without any seeming connection to reality or truth. Discovering the illusory nature of what you believe to be certain is more difficult.

Beliefs primarily formed in the intellect, or the discursive mind, support ideas of certainty that you might consider to be reality or that which is. Such thoughts tend to involve separation, for example, “I am alone, separate, and this is mine.” These thoughts seem true in themselves and seem even more correct when grouped together to support a belief. You expend energy holding on to such conclusive thoughts and might even use them to attempt to convince others to believe what you believe.