Solipsism by which that means ‘I am the only conscious mind’, epistemologically and ontologically offers that ‘everything has to exist and has to be known through my consciousness.’ This view received philosophical attention after considering thinking subject in Descartes’ doctrine and also in investigating the mind of the knower in Barkley, Kant and following German idealists such as Fichte, Schelling, and Hegel. Therefore, Solipsism could be an important philosophical problem, since ‘I perceive the outer world and also the other minds’ (...) through my conscious mind. Schopenhauer and Wittgenstein have considered this problem as ‘the border of the world for the knowing subject’ and signified it as ‘metaphysical I’. According to the transcendental philosophy of Kant, Schopenhauer believes that the existence of the representative world depends on the mind of the knowing subject. However, the knower by itself is independent of time, space and causality. In a rare epistemological situation that Schopenhauer considers in aesthetical experience, the knower is in his true state. On the other hand, under the influence of Schopenhauer, Wittgenstein in Tractatus Logico-Philosophicus introduces the role of the language in stating the border of the subject’s world; that is, the subjective experiences such as pain and emotion are perceived based on the knower’s mind. These subjective experiences also include the existence and mindfulness of others, too. Thus, the world is my world and as a conscious knower and as the conscious knower, I should exist in all the times to the end that the world exists. (shrink)