Life as defined by the Gospel is the light that came into the world. It is the Word that became flesh and this Word is God. Put simply, life is the acceptance of this light. The passage is clear in saying that light overcomes darkness, and the light was rejected by His own. Light is stronger than darkness,, but the light does not impose Himself on the human will.
Life is stronger than death, but it is in the freedom of mankind.
If one does not have this personal experience with Christ, then all the institutions and charitable organizations, all the faith and progeny, all the healthy living will not help. Life then does not start after death. Life starts from the time we accept in us the Light. Eternal life starts from Baptism, and not from Burial. St. Seraphim of Sarov defines the life in Christ as the acquisition fo the Holy Spirit.