Questions tagged [paradox]
This tag is for arguments that produce an inconsistency with common sense.
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Is there a reasonably up-to-date (as of early 2020s) review article on the Sleeping Beauty problem? [closed]
I imagine that hundreds of articles have been written by academics on the Sleeping Beauty problem, and I was wondering if there exists any review paper that summarises most or all of the most ...
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What is the root cause of Russell's paradox? [closed]
We know that Russell's paradox led to the third mathematical crisis. Later, we developed modern set theory, but only to limit the emergence of Russell's paradox, rather than to find the root of the ...
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What is the unsignifiability paradox?
Okay, so I was reading about Bhratri’s perspectivism on the Wikipedia page for Liar Paradox :
“ The Indian grammarian-philosopher Bhartrhari (late fifth century AD) dealt with paradoxes such as the ...
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Are there unsolved paradoxes?
Does someone know where to find a source that states which paradoxes are still considered unsolved without a logical fact based answer?
I checked several paradoxes on chatgpt and other ai asking what ...
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Epimenides paradox inside arithmetic
I am currently reading "Gödel, Escher, Bach", and in the book author makes the following statement:
I think the Tarski reproduction of the [liar's] paradox inside TNT points the way to a ...
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Why isn't the Liar's Paradox just accepted to be complete nonsense?
I can understand that some self-referential sentences can be sensible and have truth/false values (e.g. "This sentence is written in English." is true, "This sentence has 1,000 words.&...
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Is there a simple paradox like Russell's paradox that arises if we assume
... that for a given property P, there is a set of all and only the unordered pairs {x,y} such that x satisfies P and y doesn't satisfy P?
Clearly, to avoid Russell's paradox, we would refrain from ...
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Thomson's lamp: a useless paradox?
Thomson's lamp was mentioned at How to understand numbers that become really large? (as well as a number of posts elsewhere on SE). I have mentioned elsewhere that in addition to Cantorian infinite ...
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Can you use a theory or rule to prove that exact theory or rule is wrong?
My question is this: if say I have a rule R, is it logically possible to prove R is wrong using R? Or is it simply not possible because if the hypothesis (that R is wrong) is true, then proving R is ...
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Why does the Curry paradox require a separate solution in dialetheism?
On the Dialetheism entry on SEP, it is stated that, although dialetheism can offer a solution to the Liar Paradox (by accepting the Liar sentence as a true dialetheia), dialetheists need a separate ...
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Can natural decreasing temperatures in the world create energy to power it? [closed]
When the compound water experiences a drop in ambient temperature it freezes and becomes a solid.
When water freezes it expands.
Can you harness the energy in this expansion to produce energy such as ...
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Existentialism is real, so why does Russell's paradox matter? [closed]
"This statement is false."
It certainly looks like a truth-functional statement! So is it true or false?
The true answer is: It doesn’t matter.
If Bertrand Russell has trouble sleeping ...
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Who first proposed that the Liar sentence is neither true nor false because no sentence L which is either true or false could possibly satisfy L ⇔ ¬L?
One resolution of the Liar Paradox is that the Liar sentence is neither true nor false because no sentence L which is either true or false could possibly satisfy L ⇔ ¬L.
I couldn't attribute this ...
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Final Steps and Zeno's Paradox
In the SEP article on supertasks, it states that:
Max Black (1950) argued that it is nevertheless impossible to complete the Zeno task, since there is no final step in the infinite sequence. The ...
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Does Logical paradoxes create time [closed]
If we assume that every statement must be true or false.
The statement:
"Tomorrow I will wake up at 6:00 am",
is neither true nor false, but is impossible to find out now.
So could we argue ...
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Why is the Newcomb problem confusing?
[Note: After I made this post, the title and the post have been criticised as badly phrased and/or opinionated. I partially agreed with that and made some initial modifications. However, after others ...
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Is Russell's Paradox a semantic paradox or a syntactic paradox?
Is Russell's Paradox a semantic paradox or a syntactic paradox? I ask because of the following:
Let P be a predicate
Let SEP be the property of being a set of things that satisfies P
Let SP be the ...
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Is this a paradox or a mistake? [closed]
Zhang Hong recently asked "is there a paradox lurking in Godel's 1931 incompleteness proof" (paraphrase)? This can be answered in two ways: First, by proving quite generally that there are ...
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Is this belief about other people's beliefs paradoxical?
Is the following a paradox?
I believe that there are some people who believe in falsities.
Is what I believe true?
(if what I believe is false, then it must be true)
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Is there a paradox in the proof of Godel's incompleteness theorem? [closed]
The Gödel Incompleteness Theorem was a major discovery in modern logic that has consistently attracted the attention of scientific and philosophical circles.
However, since the Gödel Incompleteness ...
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Is Frege's axiom of unrestricted comprehension actually true after all?
Consider the following demonstration whose first line is the assumption called the axiom of unrestricted comprehension.
∀F∃y ∀x[x ∈ y iff F(x)] [OSC1]
∀F∃y [α ∈ y iff F(α)] [UI]
∃y [α ∈ y iff α ∉ α] [...
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Can a set be uncountable in one sense and countable in another sense?
Can a set be uncountable in one sense and countable in another sense? Or in other words are there senses in which the set of all real numbers satisfies the Peano Axioms? I ask because of the following,...
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What are the meanings of 'all' and 'only' in the paradox of the barber?
Barber's Paradox
In a certain town there is a barber who shaves all those who don't shave themselves, and only those who don't shave themselves. Who shaves the barber?
Let b denote the barber. Let x-...
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Has any philosopher written about how our reasoning relies on subtly incompatible assumptions depending on the kind of question we are asking?
I would like to know whether the following idea has already been formalized by some philosopher:
When we reason about questions for which we assume there is an objective or true answer, we rely ...
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Why can't the dialetheist say that the Curry sentence is both true and false?
In the SEP article for dialetheism, it is said that
A dialetheist, though, cannot simply accept that the Curry sentence is both true and false, because if it is true then ⊥ follows. Dialetheists need ...
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Approaching the knowledge of knowing using premises
The only thing(knowledge) that I know is that I don't know anything/I know nothing. (Universal Quant.). Does this mean that I don't even know that I know to begin with?
The only thing(knowledge) that ...
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If this is the answer, what is the question? [closed]
This is a philosophical riddle in the spirit of other self-referential sentences which may be “paradoxes” (or not), like the liar’s paradox.
If this is the answer, what is the question?
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Can you help me understand the masked man paradox?
The masked man fallacy (or paradox) is roughly:
Premise 1: I don't know who the man wearing the mask is.
Premise 2: The man wearing the mask is my father.
Premise 3: I know who my father is.
...
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Which paradoxes are regarded as logical paradoxes?
Here are four of what I would call logical paradoxes:
The Liar
Curry's sentence
Biscuit conditionals
Bertrand Russell's set which contains all sets which do not contain themselves
We can perhaps ...
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If the past is infinite, then I couldn't have reached the present, since the countdown to my arrival would never end
If there's an infite past, it would take an infinite time to reach this point. The countdown to my arrival would never stop, and so I would never arrive.
I did arrive. Conclusion: past events are ...
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Can one look at philosophy under the light of fictionalism? What ideas follow from this thought process? [closed]
I understand that fictionalism can be attributed to a majority of disciplines, the ones I am familiar with are modal fictionalism, mathematical fictionalism and moral fictionalism, so I was thinking ...
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"Paradoxes consume themselves" in light of the "Liar paradox"
I have a question about following excerpt from wikipedia explaining how Bhartṛhari reasoned about Liar Paradox:
Bhartrhari's solution fits into his general approach to language, thought and reality, ...
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Looped Knower Paradox?
Before I ask my question, let me elaborate on why I have the question. Consider two versions of the Looped Liar paradox.
3-Member Liar paradox:
L1: L2 is false
L2: L3 is false
L3: L1 is false
Jourdain'...
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How to make Achilles and the Tortoise argument map?
I need to make an argument map for Achilles and the Tortoise with the conclusion at the top and premises and undisclosed premises coming out of it 5-10nodes. Im stuck and dont know how to go about it ...
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Does the anticlass principle solve the Burali-Forti problem?
Justification of the foundations-of-mathematics tag: I was reading through a long text on category theory, Abstract and Concrete Categories: The Joy of Cats, and they make much of the class/set ...
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Is Schrödinger's cat a problem of how we define identity?
If we consider that a cat is composed of numerous atomic particles, defining particles in superposition presents no issue. A cat is a human construct to represent a grouping of atoms, and notions of ...
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What is the nature of the difference between a contradiction and a paradox (as apparent contradiction)?
Given the recent PhilSE question What framework or tool solves the Barber Paradox? it emerged from a number of answers including Bumble's and Mauro's that there is a technical distinction between ...
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What framework or tool solves the Barber Paradox?
The Barber Paradox is usually phrased as follows:
I know a barber whose policy is to shave everyone who doesn't shave
himself.
If a person shaves himself, the barber does not shave that
person.
If ...
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Are there different flavors of the knower paradox based on different epistemic types?
The knower paradox theme has at least two known(!) instances:
This sentence is known to be not true.
This sentence is not known to be true.
The linked SEP article reports (2) as stronger than (1) ...
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Paradox of the Loving "I": Is there any theory to answer my Paradox?
I came up with this when I was reading about the Paradox of Fiction in one of my Aesthetic philosophy texts. Here it is:
The Paradox of the Loving Individual:
(1) One experiences themselves as a ...
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Understanding F Jackson's article on "The Easy Examination Paradox"
The link for the paper is available here.
This is the case of the headmistress who says that next week, there will be a surprise exam one of the afternoons. The girl students argue that it is ...
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Does the paradox of tolerance mean that intolerance cannot be allowed in a tolerant society?
Rainer Forst describes tolerance as a social norm. So intolerant people and groups violate the social contract by denying the social norm of tolerance. See Hobbes, Locke, Kant et al on social contract....
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Is the spiral of silence an original game model?
What are the differences between the spiral of silence and the prisoner's dilemma? Can the spiral of silence be skipped, or should it jump only to score points, as in the prisoner's dilemma?
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how these two statements can be true at same time?
If you consider any two numbers that are not equal in value (2 is not 3), and it is a true statement that they are not. However, it is also true to state that they are the same: both are numbers.
You ...
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Is not knowing whether X is true inconsistent with assigning a probability to it?
I have read that it is wise to assign a non zero probability to beliefs, and not 0 or 1. This is because probability represents certainty and you cannot be certain of anything.
xxxxxx
However, if you ...
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Must all sentences be true or false?
Suppose there is a entity with which you can write down a self-contradictory sentence.Does the entity still exist?For example you know Russell's paradox?There is someone who says:"I always lie&...
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AI paradox in DKIW hierarchy [closed]
You can check this link for basic info.
(Note: 'data', 'information', 'knowledge' and 'widsom' words will be mention as shortened with first letters in this question.)
In summary:
D is the basis of W....
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Is there a couniversal solution to the predicate-theoretic version of Russell's paradox?
In set theory, let us call a solution to the problem of universal-sets-or-proper-classes a couniversal solution when it involves proposing the following:
∃U∀x((x ≠ U) ⟺ (x ∈ U))
This means that U is ...
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If this sentence is false, then it is true
Is the sentence "If this sentence is false, then it is true." false or true (even tautologically true), or is it a paradoxon? The sentence p claims (= is equivalent to?) that ~p → p which is ...
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Is there a distance so small it can't be further divided?
If I shoot an arrow at a target, at some point it will reach one half of the distance to the target. Then it will reach one half of that distance. It will continue to reach the half of the previous ...
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