There are diverse philosophical perspectives on the physical world, spanning from ancient inquiries into its fundamental constituents to contemporary debates about its reality and our knowledge of it. One major area of divergence concerns the **reality** of the physical world. **Commonsense realism** posits that there is a real world with physical objects existing independently of our minds. This view is intuitive and immensely important. However, this realism clashes with other aspects of our understanding. **Metaphysics**, as a central branch of philosophy, directly addresses the nature of reality. It asks: What is appearance and what is real? What kind of reality does the universe have – is it mind or matter or some kind of spiritual being? What kind of reality do we have as human beings?. The earliest philosophers sought to explain physical nature by identifying the one basic material out of which the world is made, such as water, air, or fire. **Plato's metaphysics** introduces a two-level view of reality, dividing it between the sensible world of changing physical objects (objects of the senses) and the intelligible world of permanent, unchanging Forms or ideas (objects of thought). According to Plato, the physical world we perceive is in constant flux, like Heraclitus's river, but the realm of Forms, such as the idea of a triangle, is eternally true and unchanging. This perspective contrasts with a purely materialistic view. Plato's philosophy suggests a reality beyond our immediate material existence, influencing the religious, artistic, intuitive, and mystical aspects of Western thought. The relationship between **appearance and reality** is a recurring theme. Vedānta philosophy in India makes a distinction between the _vyāvahārika_ (empirical or practical) and the _pāramārthika_ (transcendental or absolute) standpoints, suggesting that what appears real on an everyday level might have a different underlying reality. This is illustrated by examples like a currency note being really paper but conventionally money. Parmenides also distinguished between a world of unchanging reality and a world of appearances, an illusory world in which we live. **Physicalism** is the philosophical view that only physical things exist, denying the existence of immaterial souls, minds, or vital forces. This view asserts that everything about the world depends on arrangements of physical stuff. In contrast, **idealism** posits that all material things are reducible to mental things. **Dualism**, exemplified by Descartes, suggests that the world contains both mental and physical substances as distinct kinds. This raises the further problem of how these two interact. **Phenomenology** offers a different lens, focusing on the world as it is perceived or as "things as they appear in our experience". It is associated with philosophers like Husserl, Heidegger, Sartre, and Merleau-Ponty. Phenomenology emphasizes the importance of our subjective experience and seeks to suspend the "natural attitude," the assumption that reality is simply "out there" independent of us, through a process called _epoché_ or bracketing. Merleau-Ponty highlights the ambiguity of the body, which is neither pure thing nor pure consciousness, and emphasizes philosophy's role in returning from objective constructs to lived experience and intersubjectivity. Heidegger and Merleau-Ponty also point out that our primary way of engaging with the world is as embodied and situated human agents, not through distanced contemplation. The "phenomenological world" is described as profoundly inescapable, unlike the physical planet. **Pragmatism** focuses on our practical relation to things and the world. It reads the commitment to these practical grounds as post-Kantian or post-metaphysical. Pragmatism recognizes the finitude that follows from our existing in relation to things, and views the world as given as a world of things for us. It emphasizes that knowing a thing is having a sense of its effects or what it will do. Some forms of pragmatism, like the "mathematical pragmatism" discussed, consider the power of things and their effects beyond human concerns, including mathematical and technical relations. Peirce, a key figure in pragmatism, considered philosophy to be a "more attentive scrutiny and comparison of the facts of everyday life" and divided it into phenomenology, normative sciences, and metaphysics, aiming for a _Weltanschauung_ that can ground the special sciences. The rise of **modern science** has significantly influenced philosophical perspectives on the physical world. While early philosophers' inquiries laid the groundwork for science, science now provides evidence-based explanations for many fundamental questions. However, philosophy continues to grapple with questions that science may not be equipped to answer, such as the justification of science's presuppositions (e.g., uniformity of nature, causality), the nature of reality, and the interpretation of scientific findings. Some argue that our knowledge of the physical world through science is limited to abstract properties of structure. The concept of **metaphysical realism** suggests that there are "natural joints" in nature that our classificatory systems might latch onto. However, the "naturalness" of a natural kind can be debated. Some perspectives argue that philosophy, especially epistemology concerning empirical knowledge, is continuous with the empirical sciences, a view held by philosophical naturalists. Different philosophical traditions offer contrasting views. Indian philosophy, exemplified by the Vaiśeṣika school, while having an atomic theory, embeds it within a general spiritual outlook, considering the world a moral stage. This contrasts with a purely materialistic atomism that explains the world through mechanical motions without inherent meaning or guidance. Some contemporary philosophical approaches engage with scientific concepts. For example, "digital physics" explores the idea that the universe might be fundamentally computational. However, thinkers like Penrose argue that the human mind involves non-computable processes, suggesting the universe is not entirely digital. Ultimately, philosophical perspectives on the physical world are diverse and continue to evolve, influenced by both our everyday experiences and advancements in scientific understanding. They range from affirming an independent, mind-external reality to emphasizing the role of our experience and concepts in shaping our understanding of what constitutes the physical world. The very act of questioning the nature of reality is a defining characteristic of being human and the ongoing endeavor of philosophy.