The belief that only oneself exists is known as solipsism. Solipsism is a philosophical position that asserts that one's own mind is the only thing that can be known to exist with certainty, and everything else, including other people and the external world, is uncertain or may be considered an illusion.
There can be several reasons why someone might be convinced of solipsism or experience solipsistic thoughts:
Subjective Experience: Each individual has direct access only to their own thoughts, perceptions, and feelings. Since we cannot directly experience other minds, it might lead some people to wonder if anything beyond their own consciousness truly exists.
Philosophical Contemplation: Philosophers have explored the nature of reality and the limits of knowledge throughout history. Contemplating questions about the external world, the reliability of our senses, and the possibility of deception can lead to solipsistic doubts.
Doubting External Reality: People may experience moments of doubt about the reality of the external world due to the prevalence of illusions, dreams, and hallucinations, especially when these experiences seem vivid and compelling.
Epistemological Skepticism: Epistemological skepticism questions the reliability of knowledge and beliefs. Individuals might adopt a solipsistic stance as a radical form of skepticism, where they doubt the existence of anything beyond their immediate consciousness.
Mental Health and Isolation: In some cases, solipsistic beliefs may arise as a result of mental health issues, such as depersonalization or derealization, which can lead to a sense of detachment from oneself and the external world.
Thought Experiment: Some people might entertain solipsistic ideas as a thought experiment or mental exercise to explore the nature of consciousness and reality.
It is essential to recognize that while solipsism can be an intriguing philosophical idea, it faces significant challenges and limitations. Most people do not fully embrace solipsism as a comprehensive worldview due to the overwhelming evidence from our shared experiences and the scientific understanding of the external world.
In ordinary life, we interact with others and experience a reality that seems to be consistent and coherent. While we may have doubts about aspects of reality and knowledge, most people find it more practical and reasonable to operate with the assumption that there is an external world and other conscious beings.