Editing Thought experiment (section)

===Possibility===
In many thought experiments, the scenario would be [[nomological possibility|nomologically possible]], or possible according to the laws of nature. John Searle's [[Chinese room]] is [[nomological]]ly possible.

Some thought experiments present scenarios that are not nomologically possible. In his [[Twin Earth thought experiment]], [[Hilary Putnam]] asks us to imagine a scenario in which there is a substance with all of the observable properties of water (e.g., taste, color, boiling point), but is chemically different from water.  It has been argued that this thought experiment is not nomologically possible, although it may be possible in some other sense, such as [[metaphysical possibility]].  It is debatable whether the nomological impossibility of a thought experiment renders intuitions about it moot.

In some cases, the hypothetical scenario might be considered metaphysically impossible, or impossible in any sense at all. [[David Chalmers]] says that we can imagine that there are [[philosophical zombie|zombies]], or persons who are physically identical to us in every way but who lack consciousness. This is supposed to show that [[physicalism]] is false. However, some argue that zombies are inconceivable: we can no more imagine a zombie than we can imagine that 1+1=3. Others have claimed that the conceivability of a scenario may not entail its possibility.