Philosophy Now Forum

Hello,

I'm a big fan of metaphysics, and have studied possible world semantics and modality for years. The literature of counterfactuals has gone from David Lewis versus Saul Kripke (physical versus ersatz formulations of possible worlds) to stronger versions of ersatzism (fictionalism, the Sider Ersatz Multiverse, others), but I still like the elegance and explanatory power of David Lewis's formulation of possible worlds theory articulated in On The Plurality of Worlds in 1986. However, an even stronger formulation with physical grounding, yet still not admitting possible states of the world as concretely "actual" is something I've been throwing around. For those familiar with this literature, does this move work? Constructive criticism please.

Argument goes something like this:

1. Ideas are physical events in the brain. From physical events and processes produce ideas, speculation, fiction, and the ability to experience the world.

2. Haecceites, souls, and other essences do not exist except as concepts and tropes. There are only individuals and their bodies, including the brain and the physical connections to the brain.

3. Within the physical structure and processes of the brain, the emergent quality of the physical makeup of the brain allows for possible worlds talk with each conceivable world a physical event in the brain.

4. With this physical grounding of ideas as electrical signals, chemical events, and other processes, non-physical ideas of possible worlds, philosophy, mathematics, and fictional discussion are physically grounded in reality.

5. With this grounding principle, we can have the benefits of Lewisian possible world semantics, including explanatory power and elegance, without actually having to admit goblins, hydras, vampires, and sea monsters in our ontology, except as physical processes and events in the brain. Non-actualized states of affairs are physically grounded in reality without existing outside of our mental processes.

6. With the formulation of physical grounding in 1-5, along with contextualism and use of Wittgenstein's language games to compartmentalize our thinking, we can solve or make irrelevant many epistemological and metaphysical worries, and focus on utlity, interdisciplinary concerns, and the meta-problems of philosophy.

Two criticisms come to my mind. I hope they are constructive.

My first criticism is that your solution is possible unnecessary. I have never really understood the reason for positing possible worlds to explain modal propositions, so it is possible I am not as familiar with the literature as you would like. I get the impression they are posited to explain the truth conditions of a modal statement, and therefore require the existence of a state of affairs which makes a modal statement true. But for me, what makes modal statements true are either analyticity ( ie true by definition ) or some law of nature that is a feature of the real or actual world.

Secondly, if a solution is necessary, one problem your solution may have is that you will have to posit the real existence of possible but un-actual brain states that ground the truth statement of a modal thought. Related to this, is that such possible brain states would have to model each possible world in the same detail as a concrete possible world. Even if you allowed the brain to be in a quantum superposition of states, I doubt that they could model the range and detail of all possible worlds.

Thanks for the reply.

Regarding the first and second criticism, the reasons go back to negative existentials literature in the earliest 20th century between Meinong and Russell. The philosophy of language concern is how you can talk about non-actual things (e.g. Santa Claus, Mythical Sea Monsters) using language. In his rejection of metaphysics in the 1940's, Carnap criticized modal talk, saying it was a nonsense context, saying that any talk would be not of this world and non-actual. Quine, Kripke, Lewis, and others developed a framework to talk about non-actual but possible things based on these concerns, and with Lewis and onwards the ideas about modality have changed, along with meta-philosophy/logic approaches.

Lewis was a physicalist who wanted to ground all non-contradictory propositions in physical space (this world or elsewhere) to ground non-actual physical world states and laws on physical places that we couldn't see, or ever empirically experience or discover. But with contextualism, he doesn't have to state all parts of a world to posit it's physical existance, just the part he's talking about. I don't have to talk about the eastern part of Australia when I talk about my left foot in my apartment in Canada to know the existance of the world so context changes the truths of propositions and scope in my view.

I hope this better explains the motivation behind my view.