- Not to be confused with Soul music
Most Christians regard the soul as the immortal essence of a human - the seat or locus of human will, understanding, morality and/or personality. When a person's physical body dies, it is the soul that proceeds to the afterlife in Heaven or Hell. By analogy the Holy Spirit is the Soul of the Christian Church.
Atheistic scientists generally ignore or dismiss the soul as unsuitable for study. To be precise, the methodological naturalism of modern science is unable to handle the concept of the soul. Anything which is not material is deliberately excluded from consideration, and as the soul is not a material thing scientists accordingly refuse to study it. This has implications for the study of human psychology, despite the fact that the word "psychology" is Latin for "study of the soul." There is also the question of when the soul enters the body, as this is important for the debate on abortion from a theological position.
It should be noted that there was once a study made at the turn of the 20th century by Duncan MacDougall of the loss of weight at the time of death. The scientist doing the measurements concluded that this loss of weight (approximately three quarters of an ounce) was due to the soul leaving the body. He also did a similar experiment with dogs, but found no change in weight, which would match the Chistian concept that of God's creations on the earth, humans alone have souls. No known attempts to follow up his work have ever been made.
In religions that believe in reincarnation, such as Hinduism, Buddhism, Taoism and Jainism, all animals have souls, as they believe that a soul can be born into any animal after death. This is part of why the Jain religion and less so in Buddhism, there are strict prohibition against indiscriminately killing or harming living things.