Many people today think that when someone dies, that’s it – they no longer exist. Totally wrong!
What is death? Death happens when the soul is separated from the body. Because the body is material, it disintegrates when the soul is no longer there to keep it together. The soul, however, is spiritual (i.e. not material) and therefore cannot die. It is immortal – i.e. it will live forever. Material things disintegrate because they are made up of parts; spirits are simple and have no parts – therefore, they cannot disintegrate. The soul separates from the body when the body is no longer in a fit state to be controlled by the soul. This can happen simply by wear-and-tear or when the body is seriously damaged in an accident.
So, since the soul is immortal, the person continues to exist, except without their body. This is difficult for us to imagine because we have no personal experience of it. The natural state of a human being is to be body and soul. But, ultimately, while the body can’t do without the soul, the soul can do without the body.
Once the soul is separated from the body, it has a totally spiritual existence. It is immediately judged on its actions during life and then goes to heaven, purgatory or hell, depending on the result of this judgment. Once the soul leaves the body, it’s attitude towards God is fixed forever. If it loves God (i.e. is in the State of Grace), it will remain forever in that love. If it hates Him (i.e. is in the State of Mortal Sin), it will hate God forever. This is why it is so important to live a life of virtue, avoiding sin. Prayer and the Sacraments are so important to make sure that our soul is in a fit state to go to heaven when death arrives.
However, since God has made us body and soul, He has decided that our soul will one day be reunited with our body. This will happen on the Last Day. On that day, our body will join our soul once more – if we are in heaven, it will share in our joy; if we are in hell, it will share in our torment. This is only fair because, even though the soul is ultimately responsible for good and bad actions, the body assists the soul in carrying out these actions during life.