The reason I keep asking for specific answers to specific questions, is that I find that nobody addresses "my sample space." Even though I keep repeating it. They change it, as you did here, to include the parts I am very intentionally trying to eliminate. — JeffJo
There are two, not three, random elements. They are COIN and DAY. WAKE and SLEEP are not random elements, they are the consequences of certain combinations, the consequences that SB can observe. — JeffJo
There are two sampling opportunities during the experiment, not two paths. The random experiment, as it is seen by SB's "inside" the experiment, is just one sample. It is not one day on a fixed path as seen by someone not going through the experiment, but one day only. Due to amnesia, each sample is not related, in any way SB can use, to any other. — JeffJo
Each of the four combinations of COIN+DAY is equally likely (this is the only application of the PoI), in the prior (this means "before observation") probability distribution. Since there are four combinations, each has a prior ("before observation") probability of 1/4.
In the popular problem, SB's observation, when she is awake, is that this sample could be H+Mon, T+Mon, or T+Tue; but not H+Tue. She knows this because she is awake. One specific question I ask, is what happens if we replace SLEEP with DISNEYWORLD. Because the point that I feel derails halfers is the sleep. — JeffJo
So don't use that as a model, use the well-established methods of conditional probability. Ring a bell at noon of both days. An awake SB hears it, but a sleeping SB is unaffected in any way.
The prior probabilities of a specific bell-ring being on any member of {H+Mon, T+Mon, H+Tue, T+Tue} is 1/4. If SB hears it, H+Tue is eliminated. Conditional probability says:
Pr(H+Mon|Bell) = Pr(H+Mon)/[Pr(H+Mon)+Pr(T+Mon)+Pr(T+Tue)] = 1/3. — JeffJo
In any way that SB can assess her credence, that does not reference her position in the map, the answer is 1/3.
Using four volunteers, where each sleeps though a different combination in {H&Mon, T&Mon, H&Tue, T&Tue}? On any day, the credence assigned to each of the three awake volunteers cannot be different. and they must add up to 1. The credence is 1/3.
Use the original "awake all N days, or awake on on one random day in the set of N" problem? N+1 are waking combinations, only one corresponds to "Heads." The credence is 1/(N+1).
Change the "sleep" day to a non-interview day? It is trivial that the answer is 1/3.
I'm sure there are others. The point is that the "halfer run-based" argument cannot provide a consistent result. It only works if you somehow pretend SB can utilize information, about which "run" she is in, that she does not and cannot posses. — JeffJo
SB's answer: "Because the protocol ties one lamp to Heads-runs and two lamps to Tails-runs, among the awakenings that actually occur across repeats, the lamp I'm under now will have turned out to be a T-lamp about two times out of three. So my credence that the current coin toss result is Tails is 2/3." (A biased coin would change these proportions; no indifference is assumed.)
The coin's fairness fixes the branches and the long-run frequencies they generate. The protocol fixes how many stopping points each branch carries. Beauty's "what are the odds?" becomes precise only when she specifies what it is that she is counting.
Note on indifference: The Thirder isn't cutting the pie into thirds because the three interview situations feel the same. It's the other way around: SB is indifferent because she already knows their long-run frequencies are equal. The protocol plus the fair coin guarantee that, among the awakenings that actually occur, the two T-awakenings together occur twice as often as the single H-awakening, and within each coin outcome the Monday vs Tuesday T-awakenings occur equally often. So her equal treatment of the three interview cases is licensed by known frequencies, not assumed by a principle of indifference. Change the coin bias or the schedule and her "indifference" (and her credence) would change accordingly. — Pierre-Normand
Then what would you say it is? If you say Q, then your credence in Tails must be 1-Q, and you have a paradox. — JeffJo
The SB problem is a classic illustration of confusing what probability is about. It is not a property of the system (the coin in the SB problem), it is a property of what is known about the system. — JeffJo
That is, your credence in an outcome is not identically the prior probability that it will occur. Example:
I have a coin that I have determined, through extensive experimentation, is biased 60%:40% toward one result. But I am not going to tell you what result is favored.
I just flipped this coin. What is your credence that the result was Heads?
— JeffJo
Even though you know that the probability-of-occurrence is either 60% or 40%, your credence in Heads should be 50%. You have no justification to say that Heads is the favored result, or that Tails is. So your credence is 50%. To justify, say, Tails being more likely than Heads, you would need to justify Tails being more likely to be the favored result. And you can't. — JeffJo
I don't see any questionable appeal to the principle of indifference being made in the standard Thirder arguments (though JeffJo may be making a redundant appeal to it, which isn't needed for his argument to go through, in my view.) Sleeping Beauty isn't ignorant about frequency information since the relevant information can be straightforwardly deduced from the experiment's protocol. SB doesn't infer that her current awakening state is a T-awakening with probability 1/3 because she doesn't know which one of three indistinguishable states it is that she currently is experiencing (two of which are T-awakenings). That would indeed be invalid. She rather infers it because she knows the relative long run frequency of such awakenings to the 2/3 by design. — Pierre-Normand
"The 'ought' you mentioned, as in 'it ought to rain,' is a prediction. In contrast, the 'must' in a normative conclusion is a requirement for action—a behavioral standard that everyone ought to abide by." — panwei
In order to fully dislodge the Cartesian picture, that Searle's internalist/introspective account of intentionally contentful mental states (i.e. states that have intrinsic intentionality) indeed seem not to have fully relinquished, an account of first person authority must be provided that is consistent with Wittgenstein's (and Ryle and Davidson's) primary reliance on public criteria. — Pierre-Normand
Theoretical sentences: Describe things not directly observable, such as "Atoms are the basic building blocks of matter". They require complex background knowledge and cannot be verified by a simple, direct observation.
Observation categoricals: Sentences that involve a relationship between two events, often derived from theory and hypothesis together, such as "When the sun comes up, the birds sing".
Occasion sentences: Sentences that are sometimes true and sometimes false, like "It is raining". An observation sentence can also be an occasion sentence, as "It is cold" is true on some occasions and false on others.
"Myth of the museum" sentences: Traditional view of language where sentences are like labels for pre-existing meanings, which Quine rejects because it assumes meanings exist independently of observable behavior.
Your question "how do you know that what you think are defeaters and are progressive evolution really are?" is the right question to ask, because it highlights the difference between thinking one has a defeater and actually having one. JTB+U is built precisely to keep that distinction clear. — Sam26
I think this relates to another question. Practices and language clearly evolve over time. What causes them to change the way they do? Presumably, this is how J might relate to T and U.
In my own work I have drawn a parallel between these hinges and Gödel’s incompleteness theorems,
just as Gödel showed that no consistent formal system strong enough for arithmetic can prove all the truths it contains or even establish its own consistency from within, Wittgenstein shows that epistemic systems rest on unprovable certainties. Both reveal a structural limit on internal justification. Far from undermining knowledge, these limits are enabling conditions: mathematics requires axioms it cannot justify, and our epistemic practices require hinges that stand fast without proof.
— Sam26
I am not sure about this comparison, axioms are justified and questioned all the time. If you tried to present a system with arbitrary axioms, or ones that seemed prima facie false, no one is likely to take them seriously. The gold standard is that they seem self-evident (arguably, a sort of justification). There have been intense debates over axioms, which can take place because "justification" is not itself bound by any axiomatized system. Afterall, what are the axioms for English, German, or Latin? Axioms are assessed by intuition, consequence, coherence, explanatory success, or even aesthetics, etc. Reasons/justifications are given. — Count Timothy von Icarus
This is a false dilemma. John's subjective truth will be conditioned by his understanding of what mathematical truth is, which he has learnt through interaction with others who teach him. Unless that has happened John may have a subjective opinion, but it doesn't count as a mathematical opinion. — Ludwig V
John points to the white board, which has the figure 2 written on it. He says, "That is a prime number." We'll call the sentence he uttered S.
The cause of his use of S is a factor in determining the truth conditions. That cause is not the truth conditions, though. Or if it is, how? — frank
Do I have to know that X is true in order to use it as the T in a JTB statement? — J
I don't quite understand this. Our community ascribes false beliefs to people all the time and that's why they are called "intentional" — Ludwig V
If mathematics were merely convention, then its success in physics would indeed be a miracle — why should arbitrary symbols line up so exactly with the predictability of nature? And if it were merely empirical, then we could never be sure it applies universally and necessarily... — Wayfarer
A nice case of the “unreasonable effectiveness” is Dirac’s prediction of anti-matter — it literally “fell out of the equations” long before there was any empirical validation of it. That shows mathematics is not just convention or generalisation, but a way of extending knowledge synthetically a priori. — Wayfarer
But Kant’s point is that neither account explains why mathematics is both necessary and informative. If it were analytic, it would be tautological; if empirical, it would be contingent. The synthetic a priori is his way of capturing that “in-between” character. It also has bearing on how mathematics is 'unreasonably efficacious in the natural sciences.' — Wayfarer
A seventh misconception treats negative cases as field-defeaters (“if some reports are wrong, the thesis fails”). The thesis of this chapter is proportionate: it does not depend on unanimity or on universal accuracy. It claims that some anchored cases survive ordinary scrutiny and that these anchors stabilize the larger testimonial field. One counterexample to a weak report does not touch a different case whose particulars were independently confirmed. — Sam26
A third misconception claims “there are no controls,” implying that without randomized trials, testimony cannot carry weight. Prospective hospital protocols supply a different kind of control: fixed clinical clocks, environmental constraints (taped eyes, sealed rooms), hidden-target or procedure-bound particulars, and independent confirmation. These features limit post-hoc embroidery and allow specific claims to be checked. They do not turn testimony into lab instrumentation, but they do make some reports probative under ordinary public standards. — Sam26
Why must it be physical? this assumes from the outset that everything real must be made of particles or fields described by physics. But that is precisely the point in dispute.
Consider an analogy: in modern physics, atoms aren’t little billiard balls but excitations of fields. Yet fields themselves are puzzling entities—mathematically precise but ontologically unclear. No one thinks an electromagnetic field is a “blob of energy floating around.” It’s astructuring principle that manifests in predictable patterns, even if its “substance” is elusive. — Wayfarer
