The past event E was contingent if the causal factors (C) that produced E had the potential (at the time) to produce E or ~E. IOW, both E and ~E were possible. — Relativist

For those reading along, the standard definition of contingency is roughly just that an event is contingent if it is true in some but not all possible worlds.

This has the great advantage of not involving any notion of causality or temporality.

One of the things happening in this side conversation is that modality, temporality and causality are being mixed together with little clear idea of how they interact - that is, without a suitable logic.

One of the great advantages of possible world semantics is that it can be used to provide such logics.

The composition may change in terms of NaCl, etc., but if you do not have H2O then you do not have water. Your response? — NotAristotle

Please take a look at my earlier response to this. But I like to address this in a little different way.

Let us say some fictitious community commonly calls a particular liquid "warder". One day they decide to place the liquid in a pot and place it over a fire to see what would happen. After several hours, they notice the liquid was gone, and there was a white powder remaining. In amazement, they thought the liquid was transformed in the white powder by the heat of the fire. They called this powder "warder" as well, for them it was just a transformation into a different physical state, a solid.

Centuries past, the community developed an Atomic Theory of Matter. Soon they discovered that the liquid they called "warder" was composed of 98% H2O and 2% NaCl. When they perform the same experiment of heating in the pot, they discovered the white powder they called "warder" was compose of 100% NaCl. But even with this discovery, they continue to refer to both liquid and white power as "warder". Have they made some error in this case? What is the nature of this error? Scientifically there is no error, the composition they got right. An error in naming? But one can use the same name to refer to multiple object anytime in language, context will clarify any confusion. If you say there was some metaphysical error committed here, well what was it? I don't think we can make any sense of what a "metaphysical error" would be in this case.

For those reading along, the standard definition of contingency is roughly just that an event is contingent if it is true in some but not all possible worlds.

This has the great advantage of not involving any notion of causality or temporality. — Banno

IOW, it ignores the controversies. I have inferred that the controversies are the topic of this theead.

it ignores the controversies... — Relativist

Clarifies, would be a better word.

Your

You're conflating possibility with potential. There is no potential for a different past, but we can consider whether a past event was necessary or contingent. — Relativist

is pretty much right. Contingency is modal, potential is causal, such that if we mix the two, then we ought keep close track of which is which.

Unfortunately your definition of contingency mixes causality and and modality. If it were a definition of determinacy, it would work.

Unfortunately your definition of contingency mixes causality and and modality. If it were a definition of determinacy, it would work. — Banno

I wasn't "defining" possibility, I was discussing the ontology of possibilty - pertinent to the discussion of
"The Possibilism-Actualism Debate", referenced in the Op.

There are no metaphysically possible worlds unless there is contingency in the world, and this implies an ontological basis. You aren't obligated to participate in discussing that, but it is erroneous to suggest it's not a legitimate issue that directly relates to the topic.

RIghto. Carry on.

Sure, but in the situation we're talking about every possible world is actual, and there's no definition as to what actual means. So "actual" is meaningless. — Metaphysician Undercover

That is like saying because there is no definitive definition of “pain” the concept of pain becomes meaningless.

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Then there is the source of my empirical experience, which is not one of the possible worlds (as these are what are in the model), therefore not actual. So I concluded that it is an illusion. — Metaphysician Undercover

No one has directly seen a quark, but only theorised about them. The Merriam Webster dictionary defines “illusion” as “something that deceives or misleads intellectually”. “Illusion” would be the wrong word to describe our understanding of quarks. Similarly with theorised possible worlds.

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No, the actual world we live in is not actual, the possible worlds are actual. — Metaphysician Undercover

It depends what the expression “the actual world we live in” is referring to.

Is it referring to i) the world as we perceive it through our senses or ii) the external world that is causing our sensations?

The reasoning is inescapably circular! — Relativist

There is an escape.

Essence does not play a part in Kripke’s Rigid Designator.

As the Wikipedia article of Naming and Necessity writes:

Kripke's theory of naming, presented in his book "Naming and Necessity," argues against the descriptivist theory of names, proposing instead that names refer to objects through a causal chain originating from an initial act of naming. This means that a name's reference is fixed by its original use, rather than by a set of descriptive properties associated with the name.

Hesperus is Phosphorus is necessarily true as both refer to the same thing, Venus. That Hesperus and Phosphorus have the same identity is only known a posteriori because of empirical observation.

In Kripke’s theory of naming, there is an initial naming of a person, their baptism. In a sense, JL Austin’s performative utterance.

There is then a recursive process, a causal link between this baptised object and future objects.

For example, in possible world 5, there is a causal chain going back from Aristotle 5 to the original baptised Aristotle, meaning that Aristotle 5 is necessarily baptised Aristotle. In possible world 9, there is a causal chain going back from Aristotle 9 to the original baptised Aristotle, meaning that Aristotle 9 is necessarily baptised Aristotle. Therefore, Aristotle 5 is necessarily Aristotle 9. This means that Aristotle is a rigid designator because necessarily and causally linked to all other Aristotles.

Thereby, the baptised Aristotle = casually linked to {Aristote 1 in possible 1, Aristotle 2 in possible world 2, Aristotle 3 in possible world 3, etc}

This is an extensional definition. No intensional definition is required.

Knowing that baptised Aristotle is causally linked to Aristotle 1 tells us nothing about Aristotle’s essence.

For example that a snooker ball moves when hit by a snooker cue tells us nothing about the intrinsic nature or essence of either the snooker ball or snooker cue.

Kripke's Rigid Designator avoids such philosophical problems as to the nature of essence because based on a particular theory of naming.