Metaphysics - What is Real?

If Physics is the study of how the physical world moves and interacts, Metaphysics is the study of what the world is.

It asks the questions that science takes for granted. Science asks "How does gravity work?" Metaphysics asks "What is a 'law of nature'?"

Ontology is the study of being. It's like taking an inventory of the universe.

• Do chairs exist? Yes.
• Do numbers exist? Ideally, yes, but you can't trip over the number 4.
• Do holes exist? A hole is just the absence of stuff, so is it a "thing"?

This is the big one.

• Materialism: Everything is physical matter. Your thoughts are just neurons firing. Love is just dopamine.
• Dualism: The mind and body are separate. There is a "ghost in the machine."

If you are just atoms, how do you have Qualia—the subjective feeling of the redness of a rose? Atoms aren't red. They don't feel. How does meat become magic?

If the universe follows physical laws, and your brain is physical, then every thought you have is just the result of the previous physical state.

• Determinism: You have no free will. You were always going to read this sentence.
• Libertarian Free Will: You genuinely could have done otherwise.
• Compatibilism: A messy middle ground where we redefine "free will" to make everyone happy.

1. The Book:

• "Metaphysics: A Very Short Introduction" by Stephen Mumford.
• Does exactly what it says on the tin.

2. The Thought Experiment:

• The Ship of Theseus.
• If you replace every plank of a ship one by one, is it still the same ship? If you teleport to Mars, but the machine destroys your body here and builds a copy there, is it still you?

Next, we finish with the most practical question: How should we live? (Ethics).