Humans have long been fascinated with attempting to contact the dead. In the Old Testament, those who pursued this goal were considered possessed of a familiar spirit (demons) and called necromancers (Leviticus 20:6, Deuteronomy 18:11). God considered those who claimed to be in touch with the dead as practicing sorcery (Isaiah 47:9, Revelation 9:21) and witchcraft (Galatians 5:20).
In modern times, the curiosity of contact with the dead has led to the rise of a religious movement known as spiritualism. The movement is based on the premise that humans remain conscious and able to communicate through their spirit that survives their physical demise. Those today who claim to be a channel between the living and the dead are usually referred to as mediums or psychics.
One of the primary reasons it is impossible to communicate with dead spirits is that they cannot respond back! The Bible clearly proclaims that those who are in the grave are unconscious and powerless to do anything. They know nothing and are unable to do anything productive (Ecclesiastes 9:5 - 6, 10, see also Psalm 146:3 - 4).
Those who pass away are not aware of the trials and triumphs of their own families (Job 14:21) nor are they aware of the evil that goes on without them (2Kings 22:20). They cannot give thanks to God (Psalm 6:5), nor proclaim his truth (30:9) and because they are silent they cannot praise Him (115:17). The same absence of life happens to both animals and man when they perish (Ecclesiastes 3:19 - 20, Psalm 49:12 - 20).
Another major reason the dead cannot be contacted is that their unconscious spirits are inaccessible. Whenever a human life is formed, God creates a spirit and places it in the person (Zechariah 12:1, Hebrews 12:9) to give them the ability to think and reason. When a person dies, their spirit goes immediately back to the God who gave it (Ecclesiastes 12:7, Numbers 16:22, 27:16, Hebrews 12:22 - 23). They then await to be brought back from the dead through a future resurrection (see article on resurrections).
The James Randi Educational Foundation offered, for many years, a reward to anyone who could scientifically prove a supernatural ability like contacting the dead. More than 1,000 folks sought the reward, which climbed to one million dollars. No one, to date, has been able to demonstrate the ability to contact the dearly departed!
In the Old Testament, those who claimed to contact the dead were worthy of the death penalty (Leviticus 20:6, 27, 1Samuel 28:3). This is because they were usually influenced by a demon. Fallen spirits love to deceive gullible humans into thinking they can talk with the departed (see article on the Witch of Endor). Those who have died are not in a fiery Hell, or lounging in heaven. The Bible teaches they are all unconscious, unreachable (to anyone but God) and awaiting a resurrection back to life. They cannot be contacted by humans or demons.