Showing posts with label modal logic. Show all posts
Showing posts with label modal logic. Show all posts

Monday, January 12, 2026

Deconstructing the 'Cogito' - ChatGPT

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The Cogito as a Self-Verifying Performance: A Formalisation

The Cartesian cogito, ergo sum is often treated rather superficially: a mere sentence - "I think, therefore I am" - representing an irrefutable proof that something, at least, actually exists (me!).

Properly understood, it is a first-person (and possibly interior) speech-act that appears to secure its own truth. The aim here is to present a compact, stand-alone account that treats the cogito as a self-verifying performance, and to show by formal means why attempts to deny it even in its most minimal formulation still fail within a coherent logical framework.

1. Why Formalise?

Informal discussions of the Cogito tend to conflate three issues:

  • what “I” refers to,
  • what “thinking” amounts to,
  • the difference between uttering words and undergoing a mental act.

A formal treatment lets us separate grammar from ontology, state a minimal bridge from occurrent properties to existence, and model the cogito as a dynamic update of the reasoner’s epistemic state.


2. Language and Reading Guide

Agent: a single reasoner a.

Atomic predicates: E(a) = “a exists”; T(a) = “a is thinking now.”

Epistemic modality: Ka φ = “a knows φ.” Assume the standard S5 axiom system for the modal logic of knowledge.

Dynamic operator: [δ] φ = “after performing the private act δ of radical doubt, φ holds.”

Avowal functor: Avowa(φ) = “a now sincerely avers φ about their own occurrent state.” Avowals target self-presenting predicates such as T(a).


3. Axioms and Principles

Epistemic base (S5). Propositional tautologies; Modus Ponens; Necessitation for Ka; and axioms K, T, 4, 5 for knowledge. This is standard and neutral.

Existence Bridge. No property without a bearer (thinking implies existence):

(EB) T(a) → E(a)

This is analytic: occurrent properties presuppose something that has them.

First-person authority (immunity to error through misidentification). For self-presenting mental predicates (pain, thinking, doubting), sincere avowal yields knowledge (if you avow something you know it):

(IEM) Avowa(ψ) → Ka ψ

for ψ in the self-presenting class (including T(a)).

Doubt as a private dynamic event. The Cartesian move is an act. Let δ be “I now doubt everything doubtable.” Its postconditions capture that doubting is occurrent and self-intimating when avowed:

(D1) [δ] T(a)  - 'I'm doubting everything; I'm thinking that thought

(D2) [δ] Avowa(T(a))  - and now I also avow that thought.

Knowledge under update. A standard dynamic-epistemic inference schema:

(DEL) If ⊨ [δ](φ → ψ) and ⊨ [δ] φ, then ⊨ [δ] ψ

 - in each case, if you doubt things and the implication (φ → ψ) holds, and the antecedent φ, then so does the consequence ψ; doubting doesn't affect the underlying logic.


4. The Cogito Theorem

Claim. After performing radical doubt, the agent knows they exist:

⊨ [δ] Ka E(a)

Proof sketch with commentary.

(1) From axiom (D2), [δ] Avowa(T(a)). By (IEM), avowing an occurrent self-presenting state yields knowledge of it. With (DEL), infer [δ] Ka T(a). 

Narrative: in doubting, you thereby think; your sincere avowal confers knowledge of that thinking.

(2) From axiom (EB), T(a) → E(a).

By N (Necessitation rule), Ka(T(a) → E(a)) holds.

(3) Combine (1) and (2) by epistemic Modus Ponens inside Kato obtain:

 [δ] Ka E(a).

Narrative: you know you are thinking; you know that thinking entails existence; therefore you know you exist. QED.


5. Semantics in Plain Terms

To make the formal proof precise, we need a model of how knowledge works in terms of possible worlds.

5.1. The epistemic model.

We begin with a standard S5 epistemic model. This is just a structure with:

- a set of possible worlds W;

- an accessibility relation Ra which, for agent a, connects each world to the worlds they consider possible;

- a valuation function V that tells us which atomic facts are true in each world.

In this kind of model, the statement Ka φ (“agent a knows φ”) is true at a world if φ is true in all the worlds accessible from that world via Ra. In other words, if φ holds in every situation the agent takes to be possible, then the agent knows φ.

5.2. The doubt event.

Now add an event called δ, which represents the act of radical doubt. To describe events, we give them:

- a precondition: what must already be true for the event to occur;

- a postcondition: what the event guarantees to be true afterwards.

For δ, the precondition is trivial (it can always occur - you can always doubt). The postcondition is twofold:

- it ensures that after the event, T(a) (“a is thinking”) is true;

- it also ensures that the agent has made a sincere avowal of this fact (I assert “I am thinking”).

5.3. Updating the model.

When the event δ happens, the epistemic model is updated. This means we look at each world that was possible before and extend it to include the new facts that the event makes true. After this update, the resulting “successor” worlds all have T(a) true and also contain the avowal that T(a) is occurring.

This procedure is what specialists call a “product update,” but you don’t need the technical term. The important point is: the event reshapes the space of possibilities so that, in all futures consistent with the event, the agent is indeed both thinking (cogito) and has expressed that fact ('I think') if only to themselves.

5.4. From avowal to knowledge.

The principle (IEM - immunity to error through misidentification) states that for self-presenting mental states, a sincere avowal (“I am thinking now”) guarantees knowledge of that state. Since δ forces such an avowal, it follows that after the event, the agent knows that they are thinking. Symbolically, [δ] Ka T(a).

5.5. From thinking to existence.

The analytic bridge (EB) is always valid: if an agent is thinking, that agent exists. Because this holds in all worlds by definition, the agent also knows it. Combining this with knowledge of thinking yields knowledge of existence: [δ] Ka E(a).

5.6. Privacy of the event.

Finally, note that the event δ is private. Only the agent who performs the doubt gains this knowledge - the update in possible world structure is indexed to that agent alone. Observers outside do not acquire any knowledge just because the event occurred. This is why Descartes’ inference is strictly first-personal: it secures the doubter’s own existence to themselves, but not to anyone else.


6. Why This is Genuinely Cartesian

The account assumes neither a robust personal ego nor any claims about an external world. It requires only: (i) occurrent thinking entails existence; (ii) sincere first-person avowals of occurrent states yield knowledge; (iii) radical doubt is an occurrent state that can be avowed. The cogito is thus a dynamic self-verification, not a syllogism.


7. Pressure Points and Alternatives

7.1 Deny IEM - immunity to error through misidentification? So replace

(IEM) Avowa(ψ) → Ka ψ   - (if you avow something you know it)

with a stronger transparency principle for occurrent thought:

(TR) T(a) → Ka T(a)        - (if you're thinking, you know it).

Then (D1) yields [δ] Ka T(a), and the remainder proceeds. The cost is a heavier assumption about introspective transparency.

7.2 Deny the existence bridge? Dropping (EB) abandons a bearer-property semantics. Talk of “thinking with no thing that thinks” no longer targets the Cartesian claim; it changes the subject into fantasy.

7.3 Model “empty appearances”? To make: 

it seems that I am aware, yet nothing exists

hold, you would need a successor where T(a) is true while E(a) is false, and that violates (EB). If you also drop (EB), you lose the subject needed for first-person knowledge entirely. Either way, the attempt does not defeat the theorem within any coherent semantics.


8. Scope and Limits

This formalisation does not reassure those who want a thick, well-defined ego, diachronic personal identity, or knowledge of the external world. It isolates the minimal Cartesian kernel: perform radical doubt, gain knowledge of thinking, infer existence.

Importantly, third-person scepticism remains: nothing here licenses, for observers, “any system that utters ‘I think’ has to exist.”


Sunday, December 14, 2025

Aristotle's metaphysics in modern higher-order modal predicate logic


Aristotle, Formal Logic, and the Shape of “Essence”

1. Introduction

I already wrote about the philosophical journey from Plato to Aristotle to Aquinas. This is of interest to me because the theology of the Catholic Church remains in thrall to Aristotelian categories - there seems little appetite for updating the church's 'physics ontology' with the latest thinking from QFT or GR. Perhaps that is wise.

Anyway, in the previous post - on reflection - I didn't really explore the subtle distinctions between, for example, form and essence. But now, with GPT5.2 just introduced, perhaps we have the cognitive horsepower to make all things clear.

Aristotle would, one hopes, be pleased. So, over to GPT5.2.


2. Aristotle’s Problem (Why This Formalisation Is Needed)

Plato’s theory is pulled in opposite directions:

1) We need genuine universals: “horse” is not merely a convenient noise. There are objective joints in reality.

2) But if universals live in a separate realm (Plato), you owe a non-mystical account of how that realm explains what happens here. (And you risk regress headaches like the Third Man.)

Aristotle’s move is to keep universals real enough to explain, but to make them immanent: the explanatory principle is in the thing. That is the metaphysical brief. Now we give it a modern logical spine.

3. The Modern Apparatus

3.1 Worlds

Let W be a non-empty set of possible worlds. Let w0 ∈ W be the actual world.

3.2 Individuals (Primary Substances)

Let D be a domain of individuals. These are the candidates for Aristotle’s primary substances.

Example individual constant: b ∈ D, intended as Bucephalus (Alexander's horse).

3.3 Existence

E(x, w): “x exists in world w”.

Example: E(b, w0) says Bucephalus exists in the actual world.

3.4 Kinds (Secondary Substances) as First-Class Objects

Up to now our domain D has contained individuals — Aristotle’s primary substances (this horse, this man). But Aristotle also treats species and genera as “secondary substances”: horse, human, animal. Formally, the clean way to represent that without smuggling in Plato is to move to a two-sorted (many-sorted) logic.

We therefore extend the model so that it has two distinct domains:

D = the domain of individuals (primary substances).
K = the domain of kinds (species/genera; secondary substances). And no, this is not Plato's Forms smuggled back in!

So the model has the shape:

M = ⟨ W, w0, D, K, I ⟩

where W is the set of possible worlds, w0 is the actual world, and I is the interpretation function assigning meanings to our symbols.

Variables are typed accordingly:

x, y range over D (individuals).
k, g range over K (kinds).

Example of an individual constant: b ∈ D, intended as Bucephalus.
Example of a kind constant: kH ∈ K, intended as the kind Horse (a species).

We connect individuals to kinds with a typed “instantiation” predicate:

Inst(x, k) = “individual x instantiates kind k”. This is going to be important later.

So Inst(b, kH) reads: “Bucephalus is a horse.” This lets us talk about Aristotle’s secondary substances rigorously, without treating kinds as just more individuals in D (which would be Platonism in disguise).

3.5 Instantiation (Kind-Membership)

Inst(x, k): “individual x instantiates kind k”. As I said, note this definition as it's essential in what follows.

Example: Inst(b, kH) means Bucephalus is a horse.

3.6 Form-Tokens and Matter-Tokens

We introduce “internal principles” as values of functions on individuals.

FormOf(x): the form-token of x - (returns the structural/organising principle in the individual.)
MatOf(x): the matter-token of x - (returns the underlying stuff/potentiality in the individual.)

Example: FormOf(b) is Bucephalus’s horse-form-token; MatOf(b) is Bucephalus’s particular flesh-and-bone matter-token.

Extending the model to type the function FormOf properly

A technical but important correction: in standard model-theoretic semantics, every function symbol must have a well-defined domain and codomain that are explicitly present in the model structure.

In the earlier definition, FormOf(x) was introduced informally as “the form-token of x”. To make that precise (and to avoid collapsing forms either into individuals or into kinds), we extend the model with a third domain.

So, instead of:

M = ⟨ W, w0, D, K, I ⟩

we use:

M = ⟨ W, w0, D, K, F, I ⟩

where:

D is the domain of individuals (primary substances).
K is the domain of kinds (species/genera; secondary substances).
F is the domain of form-tokens (immanent structural/organising principles instantiated in individuals).

We can now type the functions and relations cleanly:

FormOf : D → F (maps an individual to its form-token).
MatOf : D → M (optionally: a separate domain M of matter-tokens; or treat matter-tokens as another subset/domain for full typing symmetry).
FType : F × K → {true, false} (classifies a form-token as being of the form-type corresponding to a kind).

Example: b ∈ D (Bucephalus), and FormOf(b) ∈ F is Bucephalus’s individual horse-form-token. The key Aristotelian bridge can now be written in a fully well-typed way:

Inst(x, k) ↔ FType(FormOf(x), k)

Interpretation: kind-membership is grounded in an immanent form-token (FormOf(x)), while kinds (K) merely index the classification of forms; we have not reintroduced a Platonic realm of self-standing Forms.

3.7 Form-Types as Kind-Indexed Predicates on Form-Tokens

HorseForm(f): “f is a horse-form-token”. More generally, we will use a relation:

FType(f, k): “form-token f is of form-type corresponding to kind k”.

Example: FType(FormOf(b), kH) says Bucephalus’s form-token is a horse-form-token.

3.8 Accident Predicates (For Illustration)

White(x): “x is white”. This will stand for an accidental feature.

Example: White(b) might be true (or false) depending on which horse you chose.

3.9 Necessity

□φ means: φ is true in all admissible worlds. (Standard Kripke semantics assumed.)

4. Aristotle’s Constraints (The “Design Specs”)

Aristotle needs four constraints to hold together:

(C1) Kinds must be objective. There are genuine kinds k in K such that Inst(x, k) is not mere convention.

(C2) No separate realm of Forms is required. Whatever explains Inst(x, k) must be grounded in x.

(C3) Essence is necessity. To say “P is essential to the kind k” is to say: necessarily, anything of kind k has P. So P is a necessary property for a thing to be of that kind.

(C4) Accidents vary. Some predicates (like White) are not necessary for kind-membership.

Now we encode these constraints as axioms/definitions, and see what follows.

5. The Core Aristotelian Bridge: Kind-Membership Is Fixed by Form

This is Aristotle’s anti-Plato move stated cleanly:

Axiom (Immanence - Form grounds kind-membership):

For all individuals x and kinds k, and all worlds w:

∀x ∀k ∀w ( E(x, w) → ( Inst(x, k) ↔ FType(FormOf(x), k) ) )

Example instance:

∀w ( E(b, w) → ( Inst(b, kH) ↔ FType(FormOf(b), kH) ) )

Interpretation: x is a horse (instantiates Horse) because its internal organising principle is of the horse-form type. No transcendent exemplar is doing the explanatory work.

The “universal” is not a separate thing; it’s the form-type realised in each horse.

6. Define Essence as Modal Invariance of a Kind (important!)

We now define “P is essential to kind k” in the most literal modern way: P - some predicate on individuals - holds of all existing instances of k in every admissible world.

Definition (Kind-essence - 'Essential-to'):

EssTo(k, P) ↔ □ ∀x ∀w ( (E(x, w) ∧ Inst(x, k)) → P(x) )

Here P(x) is any predicate on individuals (e.g., White(x), HasFourLegs(x), etc.).

Example 1 (accident not essence): ¬EssTo(kH, White)
This says: it is not necessary that all existing horses are white. (Correct.)

Example 2 (form-linked essence): Let PForm,k(x) abbreviate FType(FormOf(x), k). Then:

EssTo(k, PForm,k)

This says: necessarily, anything of kind k has a form-token of the k-type. 

That’s not “horses are horses”; it’s the claim that the essence of membership in a kind is tracked by form rather than matter or accident.

Logic gloss: essence vs accident (in the same formal category)

In the formal reconstruction, both essence and accident are treated as predicates of individuals — i.e. they are in the same logical category (properties that can be true of substances). The difference is their modal status.

An essential predicate is modally invariant for a kind: P is essential to kind k iff necessarily, every existing instance of k has P:

EssTo(k, P) ↔ □ ∀x ((E(x) ∧ Inst(x, k)) → P(x)).

By contrast, an accidental predicate is modally variable: it is possible to have two instances of the same kind that differ with respect to P:

◇ ∃x ∃y (Inst(x, k) ∧ Inst(y, k) ∧ P(x) ∧ ¬P(y)).

Same predicate type, different necessity profile — which is exactly why Aristotle can oppose essence to accident without inventing a second realm.

7. Matter Explains Variability, Not Definition

To represent the idea that accidents vary among members of the same kind, we add a modal possibility statement:

◇ ∃x ∃y ( E(x, w) ∧ E(y, w) ∧ Inst(x, kH) ∧ Inst(y, kH) ∧ (White(x) ∧ ¬White(y)) )

Plain English: it is possible that there exist two horses, one white and one not. Therefore White is not essential to horsehood.

This is exactly the Aristotelian distinction between what belongs to a thing as such (essence) and what belongs to it contingently (accident). Matter (and circumstance) supplies the room for difference; form supplies the stable identity.

8. The Argument as a Sequence

Step 1: Plato needs universals for explanation, but makes them transcendent, which threatens explanatory contact with particulars.

Step 2: Aristotle imposes immanence: whatever makes Inst(x, k) true must be in x itself.

Step 3: Introduce form-tokens - FormOf(x) - as internal grounds, and form-types - FType(–, k) - as the kind-indexed classification of those internal grounds.

Step 4: Axiomatically connect kind-membership to form: Inst(x, k) ↔ FType(FormOf(x), k).

Step 5: Define essence as modal invariance: EssTo(k, P) ↔ □∀x∀w((E(x,w)∧Inst(x,k))→P(x)).

Step 6: Show accidents fail the test: there are admissible worlds with horses differing in White, so ¬EssTo(Horse, White).

Step 7: Show what survives the test is form-linked: EssTo(k, x) ↦ FType(FormOf(x), k)).

Conclusion: Aristotle’s substance–essence picture can be rendered as: primary substances are form–matter composites; kind-membership is grounded in immanent form; essence is the modal profile of a kind grounded in that form; matter and circumstance explain accidental variation.

9. What This Captures (And What It Doesn’t)

This formalisation captures the heart of the Aristotelian move: the universal is immanent and explanatory, and essence is necessity rather than a heavenly object.

What it does not yet capture—because it would require additional apparatus—is Aristotle’s full-blooded teleology: forms do not merely classify; they explain capacities and ends (the four causes).

If we wanted to go further, we would add disposition predicates (e.g., CanDigestGrass(x), HasTypicalEquineLocomotion(x)) and connect those systematically to FType(FormOf(x), k). That is where “essence” becomes not just modal invariance but also explanatory depth.

10. Closing Thought

Plato made universals too far away to do their job without metaphysical baroque. Aristotle’s fix is to keep the job (explanation) but move the machinery (form) inside the thing. Once you do that, the modern modal definition of essence stops being a foreign import and starts looking like a tidy restatement of what Aristotle was aiming at all along: not a second realm, but a disciplined way of saying what cannot vary if this thing is to remain the kind of thing it is.


Here are some thoughts on the above essay from Gemini 3.


Friday, August 22, 2025

Imposter Syndrome


This morning in the library the checkout machines were out of order, so I had to do something retro: speak to a librarian at the desk. I was checking out four books for Clare.

The librarian scanned my library card, addressing me by the title printed on it: “Dr Nigel Seel.” It caught me off guard: no one usually calls me that - I rarely use the title, and when I do, it feels faintly fraudulent, like I’m impersonating some more serious person.

On the walk home, I told Clare how odd it felt. She dismissed it briskly. “They just think you’re a medical doctor,” she said, “and no one likes them anymore - they spend all their time debating pro-Hamas resolutions at their conference.”

This seemed both a little unfair and entirely in character for her.

I did feel faintly important for a second or two; I mentioned that to her as well.

But the encounter set me thinking about the PhD itself. There was a trope back in the mid-1980s, when AI was in one of its episodic summer periods, when languages like Prolog were in vogue and researchers were flushed with optimism. It was said with some truth: “what used to be a PhD thesis ten years ago is now a three-week programming project for a keen grad student and a minor paper in a conference.”

I sometimes feared my own thesis might have fallen into that category.

And yet, it was properly examined by a real logician, Professor Raymond Turner of the University of Essex: a respected name in modal logic, author of several books, an influential presence in the field. He read my thesis closely, and deemed it worthy.

What amused me at the time was that the part he found most interesting - the computational agent model I’d used, inspired by the work we were doing at STL - was something I had considered quite secondary. For me, the substance was in how the research grounded logics of belief, knowledge, perception and action in the world of situated, interacting agents. He, however, was more intrigued by the model-structure than the language-semantics.

In AI circles Turner was seen with a fond detachment. “Oh, Raymond,” they’d say. “A proper logician; he doesn’t really understand AI.” He was viewed as not quite of the community. And yet, because his work was so technically formidable, there was a sort of grudging respect, even awe. That he agreed to examine my thesis gave me a degree of credibility: borrowed gravitas.

Looking back now, I don’t think the work was as intellectually heroic as I believed at the time. But that’s how time works, with its mix of belated sense-of-proportion, misty nostalgia and hard-headed realism.

Thursday, February 06, 2025

Tea and Theodicy - by Adam Carlton


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For this meeting I had arranged to meet Claude in the upstairs room of the left-bank bookstore where I usually met with my publisher. A golden afternoon light filtered through the large window, softening the jagged lines of the Parisian skyline beyond. Dust motes danced lazily in the beams, drifting in the soothing aroma of the tea steaming between us.

Claude looked relaxed, unaware of the intellectual challenges I had prepared for him.

Ignorance is bliss, I thought.

I found the prospect quietly amusing.

“Claude,” I began, pouring the tea, “let’s start by defining some terms. It’ll give us a framework, a setting to work from.”

He nodded, his fingers wrapped around his cup, his gaze attentive.

“First,” I said, “Theodicy. It’s the attempt to reconcile the existence of evil with the notion of an omnipotent, omniscient, and omnibenevolent God. Essentially, it asks: if God is all-powerful, all-knowing, and all-good, why does He permit suffering?”

Claude nodded, relieved perhaps that I’d finally broached the subject of today’s chat.

“Second,” I continued, “Compatibilism. That’s the philosophical idea that free will can exist even in a deterministic universe. The crux of it is that an agent can be said to act freely when they do not feel constrained by external agencies or forces. 

"In other words, even if the world operates under the fixed laws of physics, as long as an individual’s choices align with their own desires and intentions, they consider themselves - and are considered - to be exercising their free will.”

Claude, I had discovered, was a sophisticated man, steeped in decades of study of the Marxist philosophical canon and Church theology. None of this was going to be news to him.

“So,” I said, leaning forward slightly, “we get to the dilemma: how can free will, with its potential for evil, coexist with an all-good God? Why allow a world where atrocities like the Holocaust are possible when, presumably, God could - and should - have actualised a better one?”

Claude set his cup down with a gentle clink and smiled at me, as if asking: is this the best you can do, this hoary old subject? 

“The Church,” he began, “has grappled with this question for centuries. There are two primary traditions we draw on: the works of Aquinas and Molinism. Let’s start with Aquinas.”

I nodded, this was going to be new to me.

“Aquinas,” Claude said, “introduced the distinction between primary and secondary causes. God, as the primary cause, is the ultimate source of all being and action, and ongoingly acts to maintain existence. However, He allows created beings to act as secondary causes within the framework of His creation, expressing the autonomy of created beings acting within the bounds of natural laws.

“This means humans are genuinely free to make choices," he continued, "even though their existence and the broader structure of reality depend on God. Understand this: God’s knowledge of future events doesn’t determine them. From His eternal vantage point, outside of time, He sees all events simultaneously. But our actions remain free within our temporal framework.”

Really? This struck me as sophistry.

“So God’s knowledge is observational rather than causal,” I said, trying to pin the idea down. “Like someone watching a play?”

“Precisely,” Claude replied. “But remember, He also wrote the play and sustains the actors in their performances.”

I thought to myself: I suppose that in the theatre we are supposed to think that the characters have free will even though it’s all scripted. But if that’s a metaphor for real life, was Shakespeare literally correct: "All the world's a stage, and all the men and women merely players…”?

Claude was continuing... 

“Now, Molinism takes a different approach. It assumes that God envisages a space of possible worlds, like that modal logic you’re so fond of with - what is it - Kripke semantics?

"So God envisages a space of possible worlds, plus the concept of ‘middle knowledge’, which refers to God’s knowledge of all these possible worlds - that is, all the ways the universe could unfold given different initial conditions and free human choices. God actualises the world that best achieves His purposes while respecting human freedom.”

“Possible worlds,” I mused. “And no doubt human freedom here is that freedom envisaged by Compatibilism. So God evaluates every potential world-scenario before deciding which one to create, to actualise?”

Claude nodded. “Exactly. He chooses a world where His purposes can be fulfilled without overriding free will. The decisions we make are our own, but the context in which we make them is part of God’s providence.”

I tapped my fingers lightly on the armrest. “And yet, in both Aquinas’s framework and Molinism, we’re left with the same question: why permit suboptimal outcomes?

"In my terms, surely there’s an optimality-ordering over possible world-histories? Surely God could tweak the parameters of free will to avoid the worst atrocities without undermining its value.”

Claude leaned back, his expression thoughtful. 

“Perhaps,” he said, “our understanding of God’s attributes needs refining. Omnipotence doesn’t, for example, mean doing the logically impossible. God can’t create free beings who are incapable of choosing evil, for instance. Nor does Omnibenevolence mean eliminating all suffering; some suffering might be necessary for the greater good, like moral growth or redemption.”

I raised an eyebrow. “But couldn’t God actualise a world where moral growth occurs without the full horrors of genocide, or where redemption is unnecessary because sin never happens?”

Claude stirred his tea while he thought about it. 

“Not if optimal good is intrinsically linked to human freedom. God values our capacity to choose - even when we choose poorly - because it’s the foundation of love, virtue, and our authentic relationships. Without it, we’re mere automata.”

I leaned back, folding my arms, ready with a crushing rebuttal. “And yet, in Heaven, we’re supposedly free, but there’s no sin or evil there. How do you square that?”

Claude’s face lit with a surprising confidence, as though this question invited a perfect rejoinder.

“In Heaven, the will is perfected. We see God as He truly is, and this beatific vision transforms our desires. Freedom remains, but the inclination toward sin is gone because sin arises from ignorance or disordered love. In Heaven, neither is possible.”

I raised my teacup in mock salute. “So, freedom without sin is possible. Why not create that state from the beginning?”

Claude smiled faintly, a trace of weariness in his eyes. 

“Because love isn’t love unless it’s chosen. The journey matters, Adam. Without it, we’d neither appreciate, nor even get to the destination.”

Later, with Claude gone and the waitress clearing the table, stacking the cups with quiet efficiency, I found myself reflecting on our conversation. 

Perhaps the Church’s theodicy wasn’t such the complete self-refuting mass of contradictions I had imagined. In its own antiquarian terms it made - maybe - a kind of sense?

An appreciation for freedom, growth and the impossible quest for perfection in this life: at least these were things both Claude and I had in common.

Monday, August 12, 2024

Free Will and the Laws of Physics

From ChatGPT

I remember it being a shock to me when I first realised that, if the laws of physics apply to human beings, then there is no possibility of genuine free will. After all, if every event in the universe, including human actions, is determined by preceding physical states governed by the laws of nature, it seems that every decision we make is the inevitable outcome of prior causes. This thought left me wondering how, under such conditions, we could possibly have free will or be morally responsible for our actions.

However, some philosophers propose a way to reconcile these two concepts through what is known as compatibilism. Compatibilism suggests that free will and determinism are not mutually exclusive. Even if our actions are determined by physical laws, we can still act freely if our actions are aligned with our desires, intentions, and rational deliberation. In this view, as long as our actions reflect our internal states and are not coerced, we can be said to have free will, even within a deterministic framework. This allows for the preservation of moral agency, as people can still be held accountable for their actions if those actions arise from their character and intentions.

Others, however, argue from a different perspective known as libertarianism. In this context, libertarianism refers to the idea that free will exists and is fundamentally incompatible with determinism. According to this view, not all events are determined by physical laws; human decisions, in particular, are seen as the result of a non-physical "will" that allows for genuine choice. From this standpoint, individuals are truly morally responsible for their actions because they could have acted differently in the same situation, allowing for a robust sense of moral agency and accountability. 

This, however, gratuitously violates the laws of physics.

On the other hand, some adopt the position of hard determinism, which accepts that determinism is true and, consequently, free will does not exist. Hard determinists argue that since every action is the result of preceding physical events, people do not possess free will in the true sense. This raises significant challenges for our understanding of moral responsibility. If individuals do not have free will, it becomes difficult to justify holding them morally accountable for their actions. In response, some hard determinists advocate for a rethinking of moral concepts, emphasising rehabilitation over punishment, or focusing on social and psychological factors in evaluating behaviour. 

In refutation, it is sufficient to observe that free will exists in virtue of the fact that people believe it does, and socially make use of the concept without there being any alternative. Socially-defined entities do, in fact, exist.

Interestingly, developments in quantum mechanics have introduced a new dimension to this debate. Some interpretations suggest that at the microscopic level, not all events are determined, and there is an element of randomness or indeterminacy. This has led some philosophers and scientists to speculate that quantum indeterminacy could provide a basis for free will. If human decisions are influenced by indeterminate quantum events, then our actions might not be fully determined by prior states. However, this introduces the challenge of randomness into the concept of free will, as it is unclear how random quantum events could give rise to meaningful control over one’s actions, which is essential for moral responsibility. 

Utterly unconvincing.

Another perspective comes from emergentism, the idea that complex systems, such as human consciousness and decision-making, can give rise to properties that are not reducible to their constituent parts. From this viewpoint, while humans are composed of particles that obey the laws of physics, consciousness and free will might emerge as real phenomena from the complex interactions within the brain. This allows for the coexistence of physical determinism and genuine moral responsibility, suggesting that free will and moral agency are emergent properties of our physical nature. 

However, this smuggles in an illegitimate, almost magical, anti-reductionism.

I think I am a compatibilist. Treating people as moral agents is an instance of the ‘Intentional Stance’. Operationally it functions as a means of social control and cohesion, without each of us having to model/manipulate internal brain states of others at a causal, neuron-synapse level - which, in any case, is utterly impractical in the foreseeable future. Psychologically, however, our sense of moral agency is not solely instrumental; instead it is part of consciousness: our sense of ourselves and others as persons, not things.


Note: Apart from the last para and comments, this post was drafted by ChatGPT. See also Molinism/Thomism.

Friday, October 18, 2019

Hegel's Absolute Idealism from an AI perspective

Amazon link

A second pass these last few days at Hegel's The Phenomenology of Mind (Spirit), a notoriously obscure but central work of the great German philosopher.

I ought to have read Hegels' book in the original German, but of course even native German speakers struggle with Hegel's technical and obscure terminology. It's never going to happen for me.

I rejected reading it in translation - it's still too hard and in any case, I'd be studying the translator's view of what Hegel really meant.

Perhaps a guide to The Phenomenology of Spirit? I have this:


Amazon link

.. but it still presupposes that the reader has grasped the problem Hegel is trying to address.

So in the end I reverted to Peter Singer (top of page) who assumes no special prior knowledge. And I learned that in the Middle-Ages under feudalism, there was no real questioning of what kind of thing the world might be (ontology) because the Bible told us that God had made it. Likewise there was no discussion about how we could come to know things (epistemology) because divine revelation was always to hand.

The rising bourgeoisie, with its campaign against superstition and arbitrary authority and its championing of transactional-rationality demanded a rethink. So we had Descartes' famous 'Cogito' and Kant's famous 'thing-in-itself' which we could never know .. and Hegel's attempt to finally resolve these issues and put Kant right.

Marxists believe that Marx in the end resolved most of these problems and I think that's right.

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There is a tradition that says that philosophers create artificial problems by over-abstracting - and then spend their careers failing to solve them. Over-abstraction means ignoring essential features of the problem - things like agency (in epistemology) and evolutionary biology (in ethics, morality and aesthetics) and social praxis (in ontology).

AI has often allowed philosophical problems of excruciating obscurity to be recast as engineering problems badly misunderstood.

What does AI (and mathematical logic) have to say about Hegel's Phenomenology of Mind?

I have some notes.

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Hegel's forms of consciousness

1. Sense-certainty

The raw elements of percepts. Like bitmaps.

The problem: uninterpreted, private and incommunicable as knowledge.

2. Perception

Codification of sensory data in a language of object and predicate names (like first-order logic). Requires a prior language. Formalised as a set of grounded atomic formulae ('facts').

The problem: where did the language come from? Not sense-experience - so must be a-priori.

3. Understanding

The interpretation of categorised sensory data in a web of knowledge and inference. Formalised as grounded atomic terms plus a relevant prior theory ('facts' + 'rules').

The problem: where did it come from? Similarly problematic to Perception above.

4. Self-consciousness

We now consider a consciousness which knows itself to be a consciousness and worries about how it comes to have facts and rules about the world. This requires a transition to named agents and epistemic logic.

Let a, b, .. be agents and K the epistemic operator.

If a knows the fact: 'the cat is in the mat' we write:

K(a, on(cat, mat)).

Trying to understand the concept of self-consciousness leads Hegel to his celebrated master-slave discussion and the notion of the 'unhappy consciousness'.

Mind becomes aware of itself as mind. It becomes aware of its theories, which give meaning to reality, as subsets of some universal theory which accurately captures all the objects and relationships which constitute universal history in its great narrative of development and progress.

Agents (individual people) are able to internalise part of this overarching theory - reflecting their partial and historically-limited experiences. But they can also be aware that absolute knowledge nevertheless exists - the upper bound of what can ever be collectively known about the universe.

Singer observes that it's difficult to understand what Hegel's ontological commitments are in his Absolute Idealism.

Consider this.

If there is some universal theory, U, then we can consider the model of that theory which comprises formal agents and their separate cognitive states in their environments over all time. The movie of the universe, if you like, expressed in a mathematical, computational sequence of states.

Yet this description is also a notated object in some 'programming language' and therefore also a theoretical construct.* Perhaps this program-plus-output is what is meant by 'universal knowledge'?

Could this be what Hegel was groping for, a century before programming languages were developed?

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* For more technically-inclined readers, what we are talking about here is a term algebra, or Herbrand universe. See the Wikipedia article.