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Questions tagged [paradox]

This tag is for arguments that produce an inconsistency with common sense.

19
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7answers
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What formal logical systems “resolve” the Liar Paradox?

Short version of my question. What formal logical systems can represent, and seem robust against, the Liar Paradox? N.B. I would like to avoid reference to truth-values, except inasmuch as they ...
20
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12answers
2k views

Motivations for dialetheism?

At the request of the moderators, I've reformulated this question to change the emphasis of the question to something perhaps a little more broad-ranging: Question. What are the major modern ...
-1
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3answers
54 views

Can two different objects at the same time be the same? [on hold]

Can two things be different and yet the same at the same time? For example, a chair (white) does not have one leg and another (black) has all of its legs. As in the question, these two things with ...
22
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6answers
3k views

Why is Aristotle's objection not considered a resolution to Zeno's paradox?

It seems to me, perhaps naïvely, that Aristotle resolved Zenos' famous paradoxes well, when he said that, Time is not composed of indivisible nows any more than any other magnitude is composed of ...
16
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7answers
3k views

Are all paradoxes reducible to one “fundamental” paradox?

I may need to refine this question, since I am mostly grappling with a murky intuition and haven't yet done the real work. When I encounter many of the well-known paradoxes, such as Zeno's dichotomy, ...
9
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3answers
504 views

Does God have the power to make identical universes through different means?

The easiest way to explain this question is with a thought experiment: Consider God, the ultimate of everything, who is wholly omnipotent (all-powerful) and omniscient (all-knowing). Let's just say, ...
4
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5answers
616 views

If I am infinitely old , can I have a father?

If I am infinitely old , can I have a father ? And can I have a brother that is infinitely older than me but younger than my dad ?
1
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4answers
2k views

Russell's Paradox & Existence of God

Russell's paradox is a famous theorem in set theory. It asserts that "the collection of all sets is not a set itself". In the other words "the set of all sets doesn't exist" in the world which ZFC ...
11
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2answers
377 views

What are the dialetheist semantics for logical negation?

This question is in a sense a follow-up, or elaboration, of the question "What are the motivations for Dialetheism?". Reflecting on the way I phrased that question, and the way I remarked on answers, ...
10
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3answers
1k views

Are there rules for dealing with self-reference “paradoxes” in logic?

My favorite paradox that leads to an endless regress, and also leads to a question: The sentence after this is true. The sentence before this is false. When contradictions appear in proofs, ...
7
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3answers
469 views

Is Ross' paradox really a paradox?

Consider the following disjunction introduction: Your room is clean. Therefore, your room is clean or your house is burnt down. Ross' paradox allegedly arises when applying this inference to ...
6
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1answer
168 views

Is it provable that epistemically possible (possible for all I know) does not imply possible?

Here is an argument that it is not. Let's start with some equivalences: X is epistemically possible iff X is possible for all I know iff not (X is impossible given what I know) iff X is not ...
6
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1answer
278 views

Is Belnap's four-valued logic technically a relevance logic?

Belnap, the American Logician, constructed a four-valued logic which is a form of relavance logic; interestingly the truth-values it takes are: true false both true & false neither ...
1
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3answers
215 views

Is this a paradox?

A and B met a genie and the genie grant each of them a wish. A's wish: I wish that B's wish is not implemented B's wish: I wish that A's wish is implemented. Is this a paradox?
10
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3answers
2k views

Can a “real” paradox exist?

Given a statement, S: "S is not true." We arrive at a paradoxical solution whether or not we assume S to be true or false. Does this automatically imply that we have made an error in logic, ...
6
votes
1answer
268 views

What is the “simple logical truth” that makes omniscience self-contradictory?

Patrick Grim claims in "Problems with Omniscience" that there is a "simple truth well established as a logical theorem", which shows that omniscience is a contradictory concept. I am failing to see ...
3
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1answer
171 views

Why is “similarity” not a logical relation? (from “Natural Kinds” by Quine)

I have two questions regarding Quine's paper “Natural Kinds”: Why isn't similarity a logical relation? Why is our ability to recognize similarity so fundamental? These two things are explained in ...
2
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4answers
1k views

Are there real paradoxes?

Paradoxes arise in mathematics; a famous one being Russells; usually its taken as a sign that the theoretical ediface needs to change. The difficult question is how; for example Russell developed his ...