Is the world real? Philosophers give 5 main answers: the world is real, no way to know, it is all in the mind, probably a simulation and virtual is real too. AskPhilosophy presents 13 arguments, from Zhuangzi to Elon Musk, reconstructed step by step, logic-checked and verified word for word against their original texts.
The 5 possible answers
Each column is one way of answering the question: what it holds and the philosophers who defend it. Click a column to see only its arguments.
The external world exists, and we have good reasons to know it.
Russell, G. E. Moore, Hilary Putnam
Nothing in our experience proves that we are not dreaming.
René Descartes, Hume, Zhuangzi
The world exists only as perceived: there is no matter behind our ideas.
Schopenhauer, George Berkeley, Vasubandhu
It is fairly likely that we live in a computer simulation.
Nick Bostrom, Elon Musk
Even if simulated, our world would be real: the question changes less than we think.
David Chalmers, O. K. Bouwsma
The arguments
Click an argument to see it step by step, with the objections and replies.
The world is real
The external world exists, and we have good reasons to know it.
3 argumentsThe real-world hypothesis is the simplest
A world of objects that exist even when unseen explains our experiences far more simply than an endless dream.
"Here is one hand": the proof of the external world
I am more certain that I have two hands here than of any skeptical premise that would deny it.
What if I were just a brain in a vat?
A brain in a vat wired to a computer would have the same inner life as mine: no experience tells the two situations apart.
No way to know
Nothing in our experience proves that we are not dreaming.
3 argumentsThe dream and the evil demon: can I be sure the world exists?
Nothing surely distinguishes waking from dreaming, and a cunning being could give me the same sensations with no outside world.
The mind has only its perceptions: the external world cannot be proved
We cannot compare a perception with an object we never perceive: so no experience links our perceptions to the world.
The butterfly dream: how do I know I am not dreaming?
In a dream everything feels real, and nothing in the present moment proves that I am awake rather than dreaming.
It is all in the mind
The world exists only as perceived: there is no matter behind our ideas.
3 argumentsThe world is my representation
Everything I know, I know as an object for a subject: the whole world exists only for a being that perceives it.
To be is to be perceived: there is no matter
We perceive only our own ideas, and an idea exists only in a mind; nothing outside a mind can resemble them.
Representation only: we perceive without any external object
We sometimes perceive without any outer object, as in dreams, and the idea of an object made of atoms contradicts itself.
Probably a simulation
It is fairly likely that we live in a computer simulation.
2 argumentsThe simulation argument: three possibilities, one of which is true
If many advanced civilizations run simulations of human histories, almost all experiences like ours would be simulated.
There is a one-in-billions chance that we are in base reality
Games will become indistinguishable from reality and run everywhere: simulated worlds would far outnumber the real one.
Virtual is real too
Even if simulated, our world would be real: the question changes less than we think.
2 argumentsEven in a simulation, the world would be real
What matters is what the simulation's computations do, not why they were built: tables and bodies exist there, made of bits.
An illusion that nothing could reveal is no illusion: the evil genius's world is our real world
We use the word "illusion" only for what can be discovered: a deception that none of our senses could detect deceives no one.
Other philosophers' positions arrive as profiles are completed. No position is presented as the winner.