Metaphysics

Watch

• The philosophy of Stoicism - Massimo Pigliucci ↗TED-Ed
• String Theory Explained – What is The True Nature of Reality? ↗Kurzgesagt – In a Nutshell
• Decoding the Universe: Quantum | Full Documentary | NOVA | PBS ↗NOVA PBS Official

Read

• Metaphysics ↗The foundational text that named the discipline, offering the first systematic inquiry into being qua being and the ultimate causes of reality.Aristotle
• Meditations on First Philosophy ↗A concise, revolutionary work that inaugurated modern metaphysics, grappling with skepticism, the existence of God, and the mind-body problem.René Descartes
• Two Dogmas of EmpiricismA seminal essay that challenged fundamental tenets of analytic philosophy, questioning the analytic-synthetic distinction and the reductionist programme.W.V.O. Quine
• Naming and Necessity ↗A groundbreaking series of lectures that redefined our understanding of necessity, reference, and identity, challenging prevailing views in metaphysics and philosophy of language.Saul Kripke
• On the Plurality of Worlds ↗A provocative and influential defense of modal realism, arguing for the existence of countless concrete possible worlds to ground modal truths.David Lewis

Voices to follow

• Timothy Williamson ↗His rigorous analytic approach to modal metaphysics and the nature of necessity has reshaped contemporary debates on reality's fundamental structure.Wykeham Professor of Logic, University of Oxford
• Kit Fine ↗A towering figure whose work on essence, ground, and the very nature of objects provides sophisticated tools for understanding what truly makes things what they are.Professor of Philosophy, New York University
• Amie Thomasson ↗Her 'easy ontology' offers a refreshingly pragmatic lens through which to view debates about existence, challenging traditional metaphysical assumptions with clarity and wit.Professor of Philosophy, Dartmouth College
• Graham Priest ↗A provocative thinker who champions dialetheism, arguing that some contradictions are true, thereby pushing the boundaries of what is considered logically and metaphysically possible.Distinguished Professor of Philosophy, CUNY Graduate Center; Professorial Fellow, University of Melbourne

Glossary

• Abstract vs. ConcreteConcrete things are physical objects you can touch, see, or experience with your senses, like a book or a tree. Abstract things are ideas, concepts, or qualities that don't have a physical form, like justice, happiness, or the number five. For example, a specific red apple is concrete, but the idea of "redness" itself is abstract.
• Cause and EffectCause and effect describes how one event (the cause) makes another event (the effect) happen. It's the relationship where something happens because of something else. For example, if you drop a glass (the cause), it will break (the effect).
• ExistenceExistence means simply "being real" or "being there." If something exists, it's part of reality. For example, your pet dog exists, but a unicorn only exists in stories and imagination.
• Free WillFree will is the idea that we have the power to make our own choices and decisions, and that our actions are not completely determined by outside forces or fate. It means you could have chosen differently. For example, choosing what to eat for lunch is an exercise of your free will, rather than being forced to pick a specific dish.
• IdentityIdentity refers to what makes something the unique thing it is, and how it stays the same even as things change around it. It's about what makes you *you* over time. For example, even though you grow older and change your clothes, your identity as "you" remains the same person.
• Mind-Body ProblemThe Mind-Body Problem is a big question about how our thoughts, feelings, and consciousness (our "mind") are connected to our physical body and brain. It asks if they are separate things or just different parts of the same thing. For example, when you feel happy (a mind state), does it directly affect your body, or are they completely different?
• RealityReality is everything that actually exists, whether we can see it, touch it, or even imagine it. It's the true state of things, not just what we think or feel. For example, the chair you're sitting on is part of reality, and so are the laws of physics that make it stand up.
• SpaceSpace is the three-dimensional area where all objects and events are located and have relative position and direction. It's essentially "where" things are. For example, the space in your room is where your bed, desk, and books are, and you can move through that space.
• SubstanceIn philosophy, substance refers to the fundamental nature or core stuff that something is made of, which exists independently and doesn't rely on anything else to be what it is. It's the underlying "whatness" of things. For example, some philosophers might say that the fundamental substance of a table is wood, or even more basically, the atoms that make up the wood.
• TimeTime is the ongoing sequence of events from the past, through the present, and into the future. It's how we measure duration and the order of things happening. For example, the time it takes to walk to school, or the sequence of events in a movie, are both examples of time in action.

Threads 8

Where this connects to other fields, and why it's worth knowing.

• Astronomy & Cosmology Science

  Roughly 95% of the universe is 'dark matter' and 'dark energy,' stuff we've never actually caught or seen, only felt tugging on things. So physics' confident map of reality is mostly a giant blank region labeled 'we don't know.' The science that seems most certain is quietly built on a huge mystery.

• Quantum Physics Science

  Tiny particles have no definite spot until someone measures them; the act of looking seems to lock reality into place. That turns a dreamy philosophy question, 'is anything really there when nobody's watching?', into something you can test in a lab. Physicists call this puzzle the measurement problem, and it drags physics straight into metaphysics.

• Psychometrics Psychology

  An IQ score, or 'g,' is really just a handy summary of how people tend to do across different tests. Treat it like a solid object physically sitting inside your skull and you've made a classic thinking error called reification, mistaking a number for a real thing. A philosophical mistake is hiding inside that single tidy score.

• AI & Technology Regulation Law

  The dusty question 'what counts as a person?' suddenly has teeth, because a court in New Zealand granted a river legal personhood, meaning someone can sue on its behalf. Now the same puzzle hangs over AI. Deciding what's 'really' a person stops being a debate and starts deciding who's allowed into a courtroom.

• Quantum Computing Technology

  A qubit, the building block of a quantum computer, sits in a weird in-between state before you measure it. But is it truly two things at once, or does it have one real answer we just can't see yet? Engineers building these machines can't dodge that question, so a piece of tech spec turns into a live argument about what 'real' even means.

• Mathematical Finance & Markets Mathematics

  To price a stock option, traders use probabilities that literally nobody believes are the real odds. The strange part: those made-up odds give the correct price anyway. It's a 'useful fiction,' a number that works perfectly even though it isn't anyone's actual guess about what will happen, which makes philosophers ask what 'real' even means.

• Cryptocurrency & Digital Money Economics

  A Bitcoin is worth something only because a crowd of people agree it is. That sounds shaky, until you realize the cash in your pocket works the exact same way. Money was never 'real' on its own; it's real because we all believe together.

• Black Holes Science

  Einstein showed there's no single "now" for the whole universe: whether two events happen at the same time depends on who's watching and how fast they're moving. That quietly destroys the idea of one shared present moment. And almost everything we think about time assumes that present exists.