Here is an answer I have carefully crafted to address the question: WHAT IS SPIRIT, EXACTLY?
Before there was logic and science there was superstition.
What is superstition but the human mind attempting to answer questions WITHOUT UNDERSTANDING of the FACTS.
In a primitive society the powers of observation play the largest role in acquiring an understanding of the world and life and death.
The very last thing a dying person does is let out a long . . . exhalation of BREATH. This is called the "death rattle."
To the family standing by the dying person, what do they observe?
1. The loved one is alive one moment
(Then they exhale air )
2. The loved one is dead.
What is the difference between a LIVING person and a DEAD person from the point of view of those observing the process of dying?
BREATH
The invisible breath.
The breath of . . .(wait for it) LIFE.
The animating force of life is invisible.
SO YOU SEE? The idea became attached to the human observers: an invisible something is the difference between living and dying.
To breathe is to reSPIRE. The SPIRIT and the breath are inextricable in the minds of primitive people.
In the Middel Ages, if a person sneezed it was thought their SPIRIT temporarily left their body and a demon might snatch it from them.
Consequently, BLESS YOU became a safeguard against that possibility.
The book of Genesis recycles the notion of "God BREATHED into his nostrils the BREATH of life and he became a living_______.
Plato (427-347 b.c.e.) was a highly influential Greek philosopher whose school of philosophy and wisdom had extraordinary influence on the world.
Plato divided up the VITAL FORCE of SPIRIT into 3 parts.
I won't go into the details--it doesn't matter at the moment.
Once Plato had introduced the division, the SPIRIT (life force) (animating invisible energy) could be only be thought of as part of a TRINITY.
One we are all familiar with today is: BODY, SOUL, SPIRIT.
The bottom line in all this?
When you don't know something you make your best guess. That guess is a stop-gap fill-in FOR FACT.
Unless you later replace the stop-gap with actual FACT it gradually becomes BELIEF.
The finalizing step in RELIGIOUS thought is the POETIC use of a BELIEF.
The metaphor of SPIRIT is all we really have with us today.
Practically every human society on Earth accepts without question the notion (and that is all it is) of SPIRIT as something
which is INVISIBLE and life-animating. But, when pressed for details you will get a shrug and a belief statement.
So, there you have it.
OPINION is what we began with, a best guess, an idea, a concept and it was carrief forward into the scientific age as ENERGY.
But--if you press a scientist or physicist for a definition of ENERGY you don't get a satisfying answer either!
It is words strung together in sentences referring to the movement of molecules at an atomic level blah blah blah.
Happy now?
I didn't think so.
The FACT of the matter is this. When you call a natural phenomenon by a TERM which is corrupted by superstition, religious metaphor and poetic exaggerations---you destroy the possibility of understanding at its most fundamental level.
You're welcome!