Proving the existence of things in reality and distinguishing them from mere perceptions within our minds/consciousness can be challenging, especially when dealing with philosophical questions about the nature of reality. However, there are some approaches and arguments commonly used to support the belief in an external reality:
Empirical Evidence: One of the most common ways to demonstrate the existence of things in reality is through empirical evidence. Observations, measurements, and experiments that can be repeated and verified by others provide strong evidence for the existence of external objects and phenomena. Scientific discoveries, technological advancements, and the practical application of knowledge are all based on the assumption of an external reality.
Consistency and Agreement: When multiple people can independently perceive, interact with, and agree upon the existence of something, it strengthens the case for its objective reality. Shared experiences and consensus among individuals provide a degree of validation for the external existence of objects and events.
Logical Arguments: Philosophers have put forth various logical arguments to support the idea of an external reality. For example, René Descartes' famous statement "Cogito, ergo sum" ("I think, therefore I am") asserts that the act of thinking itself presupposes an existing self, and consequently, an external reality.
Perception of the Physical World: Our senses provide us with information about the physical world. While it is true that our senses can be fallible and subject to illusions, they also offer us valuable information about the external environment.
Pragmatic Approach: Many people adopt a pragmatic approach to the question of reality. Even if we entertain the idea that everything could be a product of our minds, functioning and interacting with the world as if it were real is the most practical and effective way to navigate life.
Scientific Theories: Scientific theories that accurately describe and predict natural phenomena in the external world support the notion of an objective reality. These theories rely on the assumption that there is a consistent and observable external reality that can be studied and understood.
Existential Necessity: Some argue that even if the world were an illusion or a product of our consciousness, the fact that we experience it is undeniable, and thus, its existence becomes necessary in some sense.
It is essential to acknowledge that absolute certainty in the existence of an external reality may not be attainable. Our understanding of reality is often shaped by our perceptions, cognitive biases, and the limitations of our senses. However, by relying on empirical evidence, logical reasoning, and the shared experiences of others, we can build a strong case for the existence of an objective external reality.