The bodily conception is the basic principle of suffering in material existence. In Kali-yuga especially, people are so uneducated that they cannot even understand that the body is changing at every moment and that the ultimate change is called death. In this life one may be a king, and in the next life one may be a dog, according to karma. The spirit soul is in a deep slumber caused by the force of material nature. He is put in one type of condition and again changed into another type. Without self-realization and knowledge, conditional life continues, and one falsely claims himself a king, a servant, a cat or a dog. These are simply different transformations brought about by the supreme arrangement. One should not be misled by such temporary bodily conceptions. Actually no one is master within the material world, for everyone is under the control of material nature, which is under the control of the Supreme Personality of Godhead. Therefore the Supreme Personality of Godhead, Kṛṣṇa, is the ultimate master. As explained in Caitanya-caritāmṛta, ekale īśvara kṛṣṇa, āra saba bhṛtya: the only master is Kṛṣṇa, and everyone else is His servant. Forgetfulness of our relationship with the Supreme Lord brings about our suffering in the material world.