This is truly a bizarre and very peculiar story. There are certain things about it that seem to indicate that it wasn't ACTUALLY Samuel, but was a vision or an apparition. For one thing Saul couldn't see Samuel:

 

• The king said to her, "Have no fear; what do you see?" And the woman said to Saul, "I see a god coming up out of the earth." He said to her, "What is his appearance?" And she said, "An old man is coming up; and he is wrapped in a robe." And Saul knew that it was Samuel, and he bowed with his face to the ground, and did obeisance. (28:13-14)

 

There is no indication of this in the text, but I take it that Saul couldn't hear Samuel either. The woman was a medium. Usually the medium "channels" the spirit-being. The spirit-being uses the medium's vocal chords to speak.
 

Nevertheless, let's take this very unusual  and bizarre incident at face value and assume that it REALLY was Samuel, even though Saul couldn't see him. The implication would be that Samuel's soul or spirit was in existence apart from his body, and that he was conscious apart from his body. Ok...but notice the following:

 

• Then Samuel said to Saul, "Why have you disturbed me by bringing me up?" (28:15)

 

Disturbed? What was he doing? Sleeping? And if he was in heaven, why was he brought UP rather than down?

 

Samuel tells Saul,

 

• Moreover the LORD will give Israel also with you into the hand of the Philistines; and tomorrow you and your sons shall be with me; the LORD will give the army of Israel also into the hand of the Philistines." (28:19)

 

So Saul, of whom Samuel says, "...the LORD has turned from you and become your enemy" (28:16), and his sons, upon their deaths the following day will go to the same place that Samuel, the prophet of God, has gone upon his death. That place is "down", not "up". Notice that the medium saw Samuel "coming up out of the earth".
 

I also find it peculiar that Samuel appeared as an old man. I thought that when you died and went to heaven, all infirmities - including old age - no longer exist. There are no old people in heaven - at least that's the image I've received.
 

It seems to me that this incident actually illustrates the Hebraic paradigm. Both good men (Samuel) and evil men (Saul) go to the same place. This place is down not up. Samuel came up out of the earth, not down from heaven. Samuel was disturbed - this implies he was resting or asleep. He did not PHYSICALLY resurrect because Saul couldn't see him. If - I stress IF - this was indeed Samuel's disembodied soul and not some kind of vision, then I would view it as an exception, God raised enough of Samuel that at least the medium could see him. However, this incident certainly refutes the "disembodied souls of the righteous go to heaven" position. Disembodied souls (if they exist) of the righteous, and the wicked, go to the same place - the earth (Sheol, the grave), there to rest or sleep until called forth.

 

There seems to be conflicting translations about the reality of whether it was actually Samuel or not. For example, the LXX says,
 

• So Saul died for his transgressions in which he transgressed against God, against the word of the Lord, because he did not keep it, because Saul inquired of a wizard to seek counsel, and Samuel the prophet answered him;

 

There are other versions where the medium is one that had a familiar spirit, and that the familiar spirit was what Saul was inquiring of:

 

• So Saul died for his transgression which he committed against the LORD, even against the word of the LORD, which he kept not, and also for asking counsel of one that had a familiar spirit, to inquire of it; And inquired not of the LORD: therefore he slew him, and turned the kingdom unto David the son of Jesse." (1 Chronicles 10:13-14)

 

I can go either way with this. If it really was Samuel, I don't think it proves anything even close to the idea that everybody has an immortal soul that departs the body at death and goes to either heaven or hell. This passage actually reinforces the Hebrew paradigm, even if it was Samuel. He came up out of the earth, he was resting or sleeping, and Saul, when he died, went to the same place that Samuel was. Personally, because Saul couldn't see Samuel - only the medium could see Samuel - I suspect it was a vision, and had no objective reality - or - it was a familiar spirit, and not Samuel, even as some versions of the story explicitly say.