Ah, this is a good question Hagop, and one that depends on who you ask.

St. Paul speaks a little about this in Scripture, Aquinas mentions it in his Summa, and others have their own spin on these two words.

It's a little tricky because the human soul is spiritual, yet often, the soul and spirit are referred to as different things. I'll give you my very brief take on these words:

• Soul is the form of a living body that gives it life. So with all plants, animals, and humans the soul is form (making the matter, this and not that) or identity of a body, giving it life.
  
  The human soul, on the other hand, is not only the form of its body, but also a spiritual substance, which means it is a thing that can survive bodily death. It is spiritual, as opposed to physical. This is more than we can say about the souls of plants and animals.
  
  
• Spirit with a large S refers to the Holy Spirit, which is the third Person of God, theologically understood to be the love and life between the Father and the Son.
  At Baptism and Confirmation, you could say the Spirit fills our soul.
  
  
• spirit with a small s usually refers to life itself. We even see this in common secular language in phrases like He had a lot of spirit! and That's the spirit! The life of God is
  Spirit, but the life of man is spirit. In this respect, you could say the soul gives life or spirit to the body (which we share with others when we love), and the Spirit (of God) gives Life to the soul (when we accept His love).
  
  
• There's another way the word spirit is used too, and that is for non-earthly or spiritual persons, such as:
  • angels
  • demons
  • the souls of the just, and
  • souls of the damned.

  Generically, they make up what is often called the spirit world and are individually called spirits.

• Confused?

Good, so am I. I like to simplify it for myself and just refer to:

• the soul as the form or identity of the body
• the spirit as life, and
• the Spirit as the Holy Spirit.
  

In His Spirit,

Paul

Hi, Hagop —

Good question!

Let me share with you a web page on our site that address' your question:

• The Life of the Soul "...The Grace of Our Lord, Jesus Christ"

Hope this helps,

Mike