One of the speculations of modern liberals who deny the resurrection is that the disciples saw some kind of apparition, or even were having hallucinations, when they "thought" they saw Jesus alive after His death. But a supposed "hallucination" is never seen by an entire group of people at the same time, as Jesus was seen, again and again.
Jesus Himself answers those who say it was a "spiritual" resurrection. His spirit never died, so His spirit could not be resurrected. At first the disciples did, indeed, think they were seeing His "ghost," but then He showed them the scars of the spikes that had pierced His hands and feet, and He also ate part of a fish and a honeycomb before them (vv. 37, 40, 42). They could no longer doubt the reality of His bodily resurrection. It is sobering to realize that He will always bear those scars, even in His glorified body. The Scripture says that when He comes again, "they shall look upon me whom they have pierced" (Zechariah 12:10). "Behold, he cometh with clouds; and every eye shall see him, and they also which pierced him: and all kindreds of the earth shall wail because of him" (Revelation 1:7).
It is also significant that Christ did not use the more common phrase "flesh and blood" when He spoke to the disciples, but "flesh and bones." His blood had been shed on the cross as the price of our redemption (1 Peter 1:18-19).
In our own future resurrected bodies which shall be like His (1 John 3:2; Philippians 3:21), blood will no longer be needed. Blood is essential now for "the life of the flesh is in the blood" (Leviticus 17:11), but in that day "the dead shall be raised incorruptible, and we shall be changed" (1 Corinthians 15:52) to be like Him forever. HMM http://www.icr.org/articles/type/6/