Soul

The soul is an immaterial spirit that many religions claim resides in a human's body. It is supposedly responsible for consciousness, and is usually considered to be immortal. In Christianity, one's soul goes to heaven, hell, Purgatory, or simply the spirit world in the case of the Latter Days Saints movement, after death.

Origins
Some anthropologists have suggested that belief in the soul came about as early humans attempted to understand what happened when someone died. One of the first observations that can be made of a dead person is that he is no longer breathing. It appears to be no great coincidence that words for soul or spirit in many languages have etymologies linked to concepts like "air" or "wind."

Some examples of this in other languages:

Ancient Hebrew: rûach רוּח - wind; by resemblance breath, that is, a sensible (or even violent) exhalation (from e-Sword, translated as spirit in Genesis 1:2 KJV)

Swedish: Compare "ande" (spirit) and andlighet (spirituality) with the verb infinitive "att andas" (to breathe)

Counter-apologetics

 * 1) Nobody knows how the soul interacts with the body. Since it's immaterial, physical things cannot influence it, yet it somehow communicates with the brain and vice versa.
 * 2) The idea of a soul raises many questions about relativity. If the soul doesn't occupy our universe, then it shouldn't experience time. Since we do feel time, it cannot be immaterial. Since it occupies our universe, this raises many questions about its composition. Is it made of the basic particles of which all matter is comprised? If it's an entirely different type of particle, what's its mass? Is it influenced by the four fundamental forces? What's its charge? How does it manage to hold your consciousness? None of these questions have ever been answered. Therefore, using the soul to explain something is using a term that isn't defined.
 * 3) Just what information does the soul contain? Science has proven that certain parts of our physical brain are used for emotions, other parts are used for memory, logical thinking, and the pacing of one's breath and heartbeat. Damage to a certain part of the brain can drastically affect one's personality, memory, or thought processes. And if the soul contains our memories, then what is the point of our memories being stored in our physical brain as well? Is Alzheimer's or amnesia a problem with the brain or a problem with the soul?
 * 4) The introduction of certain chemical drugs to the brain can drastically change one's thoughts, memories, behavior, emotions, judgment, etc. Are these drugs somehow acting on the soul and changing properties of the soul?
 * 5) It appears that word translated as soul in the Old Testament meant life or breath, this word, nephesh is used to describe the life of animals. Though in modern Judaism and Christianity animals do not have souls, English translations of the Bible usually translate nephesh differently at different times to fit Christian theology.  The Old Testament does not support the idea of each human being having a soul that is different from an animal's life to the extent that believers assume if it supports the idea at all but see History of the Concept of Soul.