Proving the existence of things in reality and differentiating them from mere mental constructs can be a complex philosophical question. This issue is often referred to as the problem of external world skepticism. While it is challenging to provide absolute certainty, several arguments and practical approaches can help demonstrate that things exist independently of our minds/consciousness. Here are some strategies you can consider:
Empirical evidence: Use empirical data gathered through our senses and scientific instruments to demonstrate the existence of things in the external world. For example, if you want to prove the existence of a chair, you can point to the physical chair in the room and ask the person to touch, feel, or sit on it.
Consistency and coherence: Show that the existence of certain things leads to a coherent and consistent understanding of the world. If a person denies the existence of the external world, they might find it difficult to explain why they experience certain consistent patterns or why their experiences align with those of others.
Shared experiences: Point out that many people share similar experiences of the external world, which suggests a common reality. For instance, a group of people witnessing the same event can corroborate its occurrence, lending credence to the existence of an external reality.
Predictive power: Demonstrate that the concept of an external reality enables us to make predictions about future events or outcomes accurately. The effectiveness of scientific theories, for instance, is based on their ability to predict and explain phenomena in the external world.
Occam's Razor: This principle suggests that when faced with multiple explanations, the simplest one is usually the most plausible. If the existence of an external reality is a simpler explanation for our experiences than assuming everything is just a construct of our minds, it may be more convincing.
Pragmatic approach: While we might not be able to provide absolute proof of an external reality, behaving as if it exists and interacting with the world based on this assumption is more practical and conducive to living our lives effectively.
Refuting alternative explanations: Address potential solipsistic or idealistic arguments that propose everything is a product of one's mind. Dissect the flaws or inconsistencies in these arguments to demonstrate the existence of an external reality.
Despite these strategies, it's essential to acknowledge that absolute certainty might remain elusive when discussing the nature of reality. Philosophical debates around this topic have persisted for centuries. While you can present strong arguments supporting the existence of an external reality, you might not be able to conclusively convince others who hold entrenched philosophical positions. However, engaging in thoughtful discussions and considering various perspectives can lead to a better understanding of the complexity of these questions.