Computational Theory of Mind
Holds that the human mind is fundamentally an information-processing system — that cognition, and perhaps consciousness itself, is a form of computation running on the brain’s neural “hardware.”
The Great Filter
Proposes that some evolutionary or developmental step on the road from non-living matter to a galaxy-colonizing civilization is extremely improbable, “filtering out” almost every attempt — and that whether the filter lies behind us or ahead of us has very different implications for humanity.
The Chinese Room Argument
A thought experiment arguing that a computer executing a program — however convincingly it behaves — cannot be said to genuinely understand, have a mind, or be conscious, regardless of how human-like its output is.
Zoo Hypothesis
Proposes that extraterrestrial civilizations exist and are aware of humanity, but deliberately avoid contact, treating Earth and its life as a protected, unperturbed reserve.
Biological Naturalism
Searle’s own positive theory of mind: consciousness is an ordinary, higher-level biological feature caused by specific neurophysiological processes in the brain — comparable to how digestion is a biological feature of the stomach — real and physical, but not reducible to abstract computation alone.
Dark Forest Hypothesis
Proposes that civilizations stay silent and hidden because contact with an unknown civilization is existentially dangerous, making concealment and preemptive threat-elimination the only rational long-term survival strategy.
Multiple Realizability (Substrate Independence)
Holds that the same mental state can be produced by different physical systems — meaning what matters for having a mind is the right functional organization, not the specific biological material it runs on, which in principle extends to silicon.
Von Neumann Probe Argument
Argues that a single spacefaring civilization equipped with self-replicating probes could colonize the entire galaxy within a few million years — a cosmic eyeblink — making the total absence of any such probes a strong argument against an older advanced civilization ever having arisen in our galaxy.
Mind Uploading (Whole Brain Emulation)
Proposes that a mind could in principle be preserved and continued outside its original brain by scanning its full computational structure and running an equally detailed simulation on a different substrate.
Directed Panspermia
Proposes that life on Earth was deliberately seeded by an earlier advanced civilization, rather than arising locally through abiogenesis or arriving by chance via natural panspermia.