In parapsychology, the phrase has been used to describe paranormal phenomena. In the context of physical ailments, it means the use of willpower to overcome pain.
In the Bhagavad Gita, the second part of Shloka 5 in Chapter 6 states: "Atmaiva hy atmano bandhur atmaiva ripur atmanah" (the mind can be one's best friend and also one's worst enemy).
Around 172 countries affiliated to the United Nations are celebrating World Yoga Day today. TV images of hundreds and thousands of people across the world sitting in yoga postures are probably being broadcast while this post is being written.
It is important to understand what 'yoga' really means. It is not the physical exercises that go by the same name. The exercises are to prepare one's body and mind for long periods of meditation.
According to Vedanta philosophy, meditation under the guidance of an enlightened instructor can eventually lead to the 'union' (or 'yoga') of the inner Self that dwells within all beings with the Supreme Consciousness (also called Brahman or God).
Before one can practice meditation, one's mind has to be purified. To find out how to do that, one needs to be aware of the different characteristics of the mind.
In his clear and comprehensive summary of Patanjali's Yoga, Swami Bhaskarananda of the Ramakrishna Mission states the following characteristics of the mind:
1) Like water, it has a natural tendency to flow downwards and do what is harmful - like indulging in sensual, destructive and negative thoughts
2) It naturally resents being controlled or restrained
3) It inherently gets bored doing the same thing over and over again, and craves newer and more sensational experiences
4) It is full of old and bad habits; to overcome them requires a lot of will power and sustained effort
5) It is like a clean piece of white cloth that acquires any colour in which it is dipped.
Whether you are a spiritual aspirant, or a common householder, knowing and accepting the characteristics of the mind will help you to succeed in your endeavours.
In the field of investments, keeping a record of your past mistakes and analysing them with respect to the mind's characteristics will lead to better control of your impulses, which in turn will lead to more disciplined and better decision making under stressful market conditions.