The fact that we live through every detail of our past life in reverse order, brings with it that we can only now have a true knowledge of our own actions, for we experience their effects on ourselves. In the case of every action we now experience the soul-condition of the person against whom the action turned. We experience the pains and joys which we caused to other people, we experience them from within. In Kamaloca there is nothing which we did to others which does not become our own experience. Here we must apply this sentence: you will reap what you sowed.
Take one example which applies to this retrogressive experience: vivisection. This is closely connected with the materialistic direction of modern science. The position of the Middle Ages would have thought it stupid to study life by cutting of a living body and destroy in life. At that time many people, and physicians in particular, were still clairvoyant and they could therefore see through the physical body. But this power of vision was lost and because we can no longer look into the inner depths of the human organism, people began to cut it up and to dissect it. But vivisectors cut into living life. After death Karma, the law of cause and effect, becomes active. The intention that leads to vivisection comes less into consideration. The vivisector must experience in himself the results of his deeds. In kamaloka he must now endure and live through every pain which he inflicted an animal. Later on the scientific intention which prompted him to vivisect will be interwoven with his Karma.
Source Rudolf Steiner – GA 94 – Popular Occultism: Lecture 5: LIFE BETWEEN DEATH AND A NEW BIRTH – Leipzig, 3 July, 1906