Explanation: The source defines metaphysics as the branch of philosophy investigating the basic structure of reality, traditionally focusing on mind-independent aspects, and notes Aristotle's designation of it as 'first philosophy'.

Explanation: The etymological origin of 'metaphysics' from 'metá' and 'physiká' translates to 'what comes after the physics,' which is interpreted as delving into topics beyond the scope of physics, not 'the study of the physical world beyond observation.'

Explanation: Metaphysics is defined as the branch of philosophy that investigates the basic structure of reality, traditionally focusing on mind-independent aspects of the world.

Explanation: Aristotle referred to metaphysics as 'first philosophy,' emphasizing its foundational role as an inquiry into basic principles.

Explanation: The term 'metaphysics' likely originated from Aristotle's editor to indicate that the work should be studied 'after physics,' referring to its organizational placement in a collection of writings.

Explanation: The source indicates that there are two main philosophical positions regarding whether existence is a property: one views it as a property of properties, and another as a property of individuals, indicating a lack of universal agreement.

Explanation: Plato's theory of forms posits that eternal forms possess a higher kind of reality and degree of existence, with the material world being an imperfect reflection of these forms.

Explanation: Kant's understanding of categories differed from Aristotle's; Kant viewed them as fundamental principles underlying human understanding and experience, not as fundamental kinds of being. While he did propose 12 categories, the core difference lies in their philosophical function.

Explanation: Abstract objects, such as numbers and sets, are characterized by *not* existing in space and time, being immutable, and *not* participating in causal relations, in contrast to concrete objects.

Explanation: Alexius Meinong held the controversial view that nonexistent objects, such as Santa Claus and Pegasus, have being but do not necessarily have existence.

Explanation: Aristotle proposed one of the earliest theories of categories, outlining a system of 10 fundamental classifications for all entities.

Explanation: Aristotle considered substances to be the most important category, arguing that all other categories are predicated of and depend on substances for their existence.

Explanation: Concrete objects exist in space and time, undergo changes, and engage in causal relations, whereas abstract objects do not exist in space and time, are immutable, and do not participate in causal relations.

Explanation: Substratum theory, associated with John Locke, posits that particulars are a substratum combined with various properties, where the substratum provides individuality. Bundle theory, in contrast, views particulars as merely bundles of properties without a separate underlying entity.

Explanation: Mereological universalists indeed believe that every collection of entities forms a whole, resulting in countless overlapping wholes.

Explanation: The 'problem of universals' is a broader challenge concerning the ontological status of universals, questioning their independent existence or relation to individual things, not solely whether they exist only as concepts within the mind (which is the conceptualist position).

Explanation: Platonic realists assert that universals exist independently of particulars, meaning a universal such as 'red' would exist even in the absence of any red objects.

Explanation: Bundle theorists, inspired by David Hume, contend that particulars are merely bundles of properties, rejecting the idea of an underlying substratum.

Explanation: Mereological nihilists reject the existence of wholes entirely, asserting that only fundamental particles exist, arranged in certain ways.

Explanation: The 'problem of universals' is a long-standing philosophical challenge that seeks to characterize the ontological status of universals, questioning whether these general features exist independently or only in relation to individual things.

Explanation: Conceptualists offer an intermediate position, stating that universals exist, but only as concepts within the mind that are used to classify and order experience.

Explanation: According to possible world semantics, a statement is considered *possibly* true if it is true in at least one possible world, whereas it is *necessarily* true if it holds true in *all* possible worlds.

Explanation: Spacetime absolutism, also known as substantivalism, indeed views spacetime as a distinct object, often conceptualized as a container for all other entities.

Explanation: The B-series theory of time views time as static, ordering events by 'earlier-than' and 'later-than' relations without an inherent difference between past, present, and future. The A-series theory, conversely, posits the real flow of time and categorizes events into past, present, and future.

Explanation: Perdurantism views material objects as four-dimensional entities that extend through time, composed of different temporal parts. Endurantism, in contrast, proposes that material objects are three-dimensional entities that are wholly present at each moment.

Explanation: The regularity theory of causation, influenced by David Hume, states that causation is simply a constant conjunction of phenomena, where the mind infers a causal link from observed consistent sequences of events.

Explanation: Many metaphysicians use the concept of 'possible worlds' to analyze modal statements, defining a possible world as a complete and consistent way the totality of things could have been.

Explanation: Spacetime idealists believe that space and time are constructs of the human mind, created to organize and make sense of reality, in contrast to spacetime realists.

Explanation: The B-series theory of time views time as static, ordering events by 'earlier-than' and 'later-than' relations without an inherent difference between past, present, and future.

Explanation: Eternalism holds that past, present, and future entities are all equally real, existing simultaneously in a four-dimensional block universe, whereas presentism asserts that only entities in the present moment truly exist.

Explanation: Cartesian dualism asserts that minds and bodies are distinct substances that *are* capable of causally interacting with each other, though they can exist independently.

Explanation: Metaphysical idealism is indeed a monist position that posits everything is mental or mind-dependent, including physical objects.

Explanation: The 'hard problem of consciousness' specifically questions how physical systems can produce *subjective, qualitative* experiences, not objective, third-person observable ones.

Explanation: Incompatibilism asserts that free will and causal determinism *cannot* coexist, meaning they are mutually exclusive. Compatibilism is the position that argues they can coexist.

Explanation: The mind-body problem is a central challenge in metaphysics that seeks to clarify the relationship between physical phenomena (like the brain) and mental phenomena (like thinking, perceiving, and feeling).

Explanation: Materialism is a monist position that states all reality is at its core material, often explaining mind in terms of brain states or functional roles.

Explanation: The 'hard problem of consciousness' questions how physical systems, such as brains, can produce phenomenal consciousness, which refers to subjective, qualitative experiences.

Explanation: Hard determinists conclude that free will does not exist because true choice would be absent if everything is predetermined, aligning with the incompatibilist view that free will and determinism cannot coexist.

Explanation: Naturalized metaphysics, closely associated with Willard Van Orman Quine, views metaphysics as continuous with the empirical sciences, generalizing their insights and making their underlying assumptions explicit.

Explanation: David Hume, from an empiricist perspective, criticized metaphysics for attempting to gain knowledge *outside* the realm of sensory experience, arguing it relies on dubious intuitions about a realm beyond empirical knowledge.

Explanation: Logical positivists argued that metaphysical statements are *meaningless* because they make no testable predictions about experience and thus cannot be verified.

Explanation: Metaphysical or ontological deflationism indeed suggests that metaphysical disagreements are merely verbal disputes about different ways to describe the world, lacking substantive consequences for the nature of reality itself.

Explanation: Metaphysics has faced criticisms questioning the reliability of its methods and the meaningfulness of its theories, often due to the abstract nature of its topics and difficulty in empirical verification.

Explanation: Immanuel Kant criticized traditional metaphysics for attempting to gain insight into the mind-independent nature of reality, arguing that human knowledge is limited to the realm of possible experience.

Explanation: Plato's theory of forms posited that eternal forms or ideas possess the *highest* kind of reality, with the material world being merely an imperfect reflection of these forms.

Explanation: Boethius significantly influenced medieval Western philosophy by proposing that universals could exist both in matter and in the mind, thereby attempting to reconcile Plato's and Aristotle's theories.

Explanation: Avicenna's contributions included examining the contrast between existence and essence and distinguishing between contingent and necessary existence. Substance dualism, distinguishing mind and body as independent entities, was developed by René Descartes.

Explanation: Baruch Spinoza's monist philosophy rejected Descartes' dualism, proposing that there is only one substance possessing both physical and mental attributes that develop in parallel without direct causal interaction.

Explanation: Gottfried Wilhelm Leibniz's monadology proposed that the universe is a collection of *simple*, fundamental substances called monads, which are synchronized but *do not* causally interact.

Explanation: The 'revolt against idealism' in early 20th-century analytic philosophy, led by Bertrand Russell and G. E. Moore, indeed argued for the existence of a mind-independent world, opposing prevailing idealistic philosophies.

Explanation: Logical atomists, including Bertrand Russell and the early Ludwig Wittgenstein, conceived the world as a multitude of *atomic* facts, suggesting a fundamental, irreducible structure of reality, rather than complex, interconnected facts.

Explanation: Early explorations of metaphysical themes can be found in the Upanishads, originating in ancient India around the 7th century BCE.

Explanation: René Descartes developed substance dualism, a metaphysical theory proposing that body and mind exist as independent entities that causally interact with each other.

Explanation: Gottfried Wilhelm Leibniz introduced the concept of possible worlds and articulated a metaphysical system known as monadology.

Explanation: Logical atomists, including Bertrand Russell and the early Ludwig Wittgenstein, conceived the world as a multitude of atomic facts, suggesting a fundamental, irreducible structure of reality.