When a person dies we may think about the impermanence of life, but this is not the realization of the truth of impermanence, the truth that each reality that arises because of its appropriate condition falls away. Lord Buddha teaches us what life really is : it is one moment of experiencing an object through one of the six doorways, the doorways of senses and the mind-door. Visible object, sound, smell, taste, tangible object and thinking are dhammas appearing at this moment (through the six doorways), but we are ignorant of the truth.