What is the difference between an animal brain and a human brain of similar size? Science hasn't been able to explain the vast difference in thinking ability between the animal brain and the human mind. But the Bible talks about a spiritual component God gives to every person (Zechariah 12:1 Zechariah 12:1The burden of the word of the LORD for Israel, said the LORD, which stretches forth the heavens, and lays the foundation of the earth, and forms the spirit of man within him.
American King James Version×). The Bible teaches that this spirit in man imparts aspects of the human mind, including self-awareness, intellect, creativity, personality and temperament—everything that enables human accomplishment and knowledge short of true spiritual understanding (1 Corinthians 2:11 1 Corinthians 2:11For what man knows the things of a man, save the spirit of man which is in him? even so the things of God knows no man, but the Spirit of God.
American King James Version×).
Ecclesiastes 12:7 Ecclesiastes 12:7Then shall the dust return to the earth as it was: and the spirit shall return to God who gave it.
American King James Version×mentions this spirit, saying that the spirit of man returns to God upon death. Some erroneously interpret this as a reference to righteous souls going to heaven. However, the context shows this interpretation is wrong. For one thing, it says that the spirit of everyone who dies, not just the righteous, goes back to God who gave it. The preceding verses speak of aging and death taking their natural course in every person.
As our booklet What Happens After Death? explains, Paul wrote that the righteous dead wait in their graves until the resurrection (1 Thessalonians 4:14-18 1 Thessalonians 4:14-18  For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him.
 For this we say to you by the word of the Lord, that we which are alive and remain to the coming of the Lord shall not prevent them which are asleep.
 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first:
 Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.
 Why comfort one another with these words.
American King James Version×). And since Christ comes to the earth to reign, the resurrected saints will also be on the earth. Heaven isn't the reward of Christians. (See also our booklet Heaven and Hell: What Does the Bible Really Teach?)
This verse of Ecclesiastes 12 is part of the chapter's conclusion. In its entirety, the verse reads, "Then the dust will return to the earth as it was, and the spirit will return to God who gave it." Upon death, the human body decomposes into the dust from which it was created and the spirit in man goes back to God.
What is the spirit in man? Is it the man himself? If that were the case, Ecclesiastes 12:7 Ecclesiastes 12:7Then shall the dust return to the earth as it was: and the spirit shall return to God who gave it.
American King James Version×would not make sense. It plainly says that the body decomposes. Is the spirit in man an immortal soul? Much of mainstream Christianity has adopted the idea of an immortal soul from ancient pagan religion; it is not taught in the Scriptures.
Why would the spirit of man return to God upon death? Consider how God will resurrect the dead. He will not simply put life back into dead bodies. For even if the body remains intact upon death, it will eventually decompose, just as Ecclesiastes 12:7 Ecclesiastes 12:7Then shall the dust return to the earth as it was: and the spirit shall return to God who gave it.
American King James Version×stated. That is, the bodies of most people will no longer exist by the time of the resurrections.
It is likely, therefore, that the spirit in man serves as the permanent record of every human being, by which God will resurrect him or her at the appointed time (1 Corinthians 15:23 1 Corinthians 15:23But every man in his own order: Christ the first fruits; afterward they that are Christ's at his coming.
American King James Version×). By way of analogy, it's possible to recreate a destroyed building if one has the blueprints of the original. Similarly, God is able to recreate a person by the record preserved in the spirit in man.