Early yoga texts and teachings help us understand more about the concept of mind, body and spirit.
According to many texts and teachings…
The physical body is exactly what you see when you look in a mirror plus its internal contents and bodily systems for example the respiratory, digestive, skeletal, neuromuscular, endocrine, urogenital, cardiovascular, nervous and hormonal.
The physical body passes through five stages of existence these are birth, growth, change, decay and death. It sounds like a harsh reality but, everyone is born, we all grow, changes and development constantly occur, then at some point the body begins to decay as the aging process sets in and then eventually the physical body dies.
The astral body is not visible when we look in the mirror, it does not exist in the form or matter, the astral body contains the intellect, the subconscious mind and the ego. The astral body is an energetic body it can experience pain and pleasure, the astral body stores information and memories from our current life.
The Karmic or Causal body is beyond description and can be difficult to comprehend; the causal body is often regarded as the soul. Vedanta and early yoga teachings believe that we have had many incarnations. For each incarnation the soul remains fundamentally the same. The causal body or the soul contains many subtle imprints from each previous life. The causal body is the seed of your creation.
The physical body therefore acts as a vessel; it is the transport for the astral and causal body.
It is believed by early yogis that the physical body and astral body change and evolve during each life, the causal body remains fundamentally the same only with each incarnation it will contain the imprints from the previous life, it is these imprints that shape and act as a guide for the next incarnation.
Understanding these three bodies will help us to understand the Five Koshas or layers of existence also sometimes referred to as the five bodies.