Q&A: Are there such things as ghosts?
ANSWER: [Author's note: I am responding to this question from the perspective of the Bible, and not from personal experience or any other source.]
Technically speaking the Greek language (which the New Testament was written in) doesn't have a unique word for "ghost." In the passage you referenced (Luke 24) the disciples thought they were seeing a "spirit" when Jesus appeared to them on the evening of the Resurrection. The Greek word is the same as is used for the Holy Spirit but sometimes English translators will render it as "ghost" depending on what is happening in the passage. I believe it's an unfortunate choice of words. "Spirit" is much more accurate in this case.
There is one other Greek word translated "ghost" in English Bibles and it occurs in the Gospel accounts when the disciples saw Jesus walking on the water. One example is below:
Matthew 14:26 (ESV)
But when the disciples saw him walking on the sea, they were terrified, and said, “It is a ghost!” and they cried out in fear.
This is the Greek word phantasma (where we get our word phantom) and is defined as an appearance or apparition. Quite honestly we don't know what the disciples thought they saw because the Greek simply says they saw "an appearance." But we know they were terrified.
Even if the disciples did think they were seeing a ghost, that doesn't mean that the Bible affirms the existence of such things. There is a huge difference between the Bible telling a story, and actually teaching a truth. And nowhere in the Word of God is the idea of ghosts affirmed in the sense of making a truth claim.
In folklore a ghost is a disembodied human being. And according to the Bible it is possible for someone to exist without their corporeal body, and the Apostle Paul refers to such a person as "unclothed" in 2 Corinthians 5. Such individuals are not called "ghosts." They are simply those who have died in Christ and are awaiting their eternal bodies, which they will receive at the time of the Rapture of the Church. (See 1 Thessalonians 4:13-18)
So the Bible gives no credence to the existence of ghosts as they might be portrayed in popular movies or books.
Does this bring up more questions? Post them below.