Today, a meter is defined as the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second. A second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. So in effect, we have substituted the caesium-133 atom for the standard meter bar. The same points could still be made, but we’ll stick with the meter bar for simplicity. — John MacFarlane
Possible worlds are stipulated. We stipulate the counterfactuals. So, we would have to stipulate that the laws of nature are the same or different. — Noah Te Stroete
If we assume that accessibility relations are the same across possible worlds, then that assumes a form of scientific essentialism. This is because rigidity and necessary conditions are guaranteed through adhering to properties that are immutable, such as the laws of physics and nature. — Wallows
But accessibility relations are determined by the properties of the modal logic in use (basically which worlds can quantify over other worlds given certain properties like transitivity or Euclideanness), they aren't properties of the possible worlds themselves, right? I'm not sure if this is essentialism. — MindForged
What do you mean by “accessibility”? — Noah Te Stroete
All what seems like hand-waiving? — Noah Te Stroete
Setting up a possible world to conform (altering the accessibility relations) to a certain set of circumstances instead of having it (rightly so) , the other way around of the world dictating or determining states of affairs. — Wallows
All this. It’s difficult for me to parse. — Noah Te Stroete
... although the man (Nixon) might not have been the President, it is not the case that he might not have been Nixon (though he might not have been called ‘Nixon’). [1, p. 49] — Kripke, Naming and Necessity
We can logically conceive of him being called “Smith” in a possible world that he was adopted. However, “Nixon” is still a rigid designator because that is how we know we are talking about the same person. It’s a rigid designator, but that name given to him is a contingent truth. — Noah Te Stroete
So, a meter stick is defined circularly — Wallows
then how can we know that the same properties apply in any other possible world? — Wallows
Everything is defined circularly, by the way. That's how definitions work. All the words in a dictionary are defined in the dictionary by other words being defined in the dictionary. If you don't have any intuitive semantic grasp of some of those words, it's just one big circular mess and you'd be stuck. — Terrapin Station
It’s a contingent truth that he was president because we can logically conceive of him not being president. It’s a necessary truth that he is not a cow, for example. We wouldn’t be talking about Nixon then. — Noah Te Stroete
The metre stick is used to set a specific length, designated rigidly by the name "Metre".
A metre is hence the same length in all possible worlds. — Banno
necessary and contingent truths are just another way of saying primary and secondary qualities aren't they? — Hanover
The metre stick is used to set a specific length, designated rigidly by the name "Metre". — Banno
Get involved in philosophical discussions about knowledge, truth, language, consciousness, science, politics, religion, logic and mathematics, art, history, and lots more. No ads, no clutter, and very little agreement — just fascinating conversations.