Plato argues that the soul survives in the afterlife without the body. The soul that we all possess lived in the world of perfect forms prior to entering this world. As the soul entered the world, it travelled through the river of forgetfulness. This is where you gain innate knowledge. Moreover, Plato believes in the Cycle of Opposites. Everything has an opposite, for example, life comes from death and death comes from life. So therefore, we know there is immortality of the soul. It is a constant cycle of life and death