73 Can you prove anything in philosophy? 2011-06-07T22:21:23.047

42 Does a negative claimant have a burden of proof? 2011-07-01T03:49:38.643

22 What is the difference between "reductio ad absurdum" and "proof by contradiction"? 2011-06-21T03:38:33.520

14 How to prove you are an atheist? 2012-06-08T15:51:01.170

14 Does every truth have to be provable based on evidence? 2019-11-10T19:18:06.863

13 What is the relation between proof in mathematics and observation in physics? 2015-12-23T10:57:58.557

12 How to prove (A v B), (A → C), (B → D) therefore (C v D) 2019-09-27T04:34:33.723

11 How do we know if a mathematical proof is valid? 2014-08-20T08:55:09.053

11 Is a proof still valid if only the author understands it? 2016-11-16T21:25:13.150

11 Can we logically prove that anything exists? 2018-08-04T12:52:20.747

11 Is watching an amputated limb regrow proof of the supernatural? 2020-09-22T05:08:14.187

10 Are there rules for dealing with self-reference "paradoxes" in logic? 2015-06-30T03:29:37.340

10 What makes something mathematics? 2015-07-23T16:59:11.080

9 Claims that we know (virtually) nothing - can they be refuted? 2012-02-20T17:24:18.280

9 Why is Modus Ponens valid? 2012-07-03T00:48:47.063

9 What is the correct, pragmatic, reasoning response to conspiracy theories? 2013-11-17T08:39:48.583

8 How does one prove De Morgan's laws for quantifiers? 2015-09-26T17:10:52.137

7 Are there any potential flaws in the definition of validity as "provable or falsifiable"? 2011-06-17T14:52:43.897

7 Are there any known deficits of "relevant logic"? 2012-04-15T23:04:30.367

7 In what sense are proofs just arguments that convince us, not arguments that establish truth? 2014-01-12T07:35:38.200

7 What is the difference between mathematical reasoning and philosophical reasoning? 2015-01-19T02:15:36.747

7 How do proofs about logic fit into a logical framework? 2020-01-16T21:01:35.257

6 What does it mean that a claim is a claim of nonexistence? 2011-07-08T13:01:29.720

6 Is it possible to prove that the universe either is or isn't a simulation? 2015-05-29T21:50:22.220

6 The difference between argument, inference, deduction and proof? 2015-08-27T19:55:22.837

6 Given P ∨ ¬ P prove (P → Q) → ((¬ P → Q) → Q) by natural deduction 2015-09-11T12:38:31.193

6 Can something "count" as TRUE without support by logic and empirical data? 2015-11-24T19:27:33.280

6 In Fitch, how does one prove "(P → Q)" from the premise "(¬P ∨ Q)"? 2016-11-20T07:08:04.203

5 Does Descartes prove that he isn't dreaming? 2012-10-20T00:34:24.853

5 Origin of the idea that something can't be proved, only disproved 2012-11-06T10:29:39.930

5 Establishing Incompletenes of Modal LPC 2013-01-09T23:04:32.070

5 Is there such a thing as provability of provability? 2013-11-17T12:42:40.473

5 Rebuttal for modus ponens 2014-09-12T13:40:22.667

5 Multiple universal quantifiers in an argument 2015-09-06T10:11:49.187

5 Does predicate logic have truth tables? 2015-10-02T15:18:40.133

5 What exactly are the identity rules in logic? 2015-10-31T03:01:55.047

5 Is any aspect of the supernatural testable? What level of proof is possible for the supernatural? 2015-12-08T23:37:30.387

5 What is the difference between everyday realism and metaphysical realism? 2016-04-06T16:37:02.423

5 A Paradox of Precision? 2016-06-08T06:32:53.410

5 How does one prove properties of soundness and completeness for a logic using proof-theoretic semantics? 2016-11-27T07:15:27.213

5 Philosophical interpretation of the cut rule of Sequent Calculus 2017-02-16T12:23:37.107

5 What is behind Girard's idea of distinguishing implication ( ⇒) and entailment (⊢) without separating language and meta-language? 2017-02-26T16:37:00.260

5 Are axioms tautologies? 2017-04-18T22:18:12.080

5 What is the nature of proof in mathematics? 2017-07-09T01:18:50.103

5 Does anyone have a proof checker they prefer using for modal logic? 2018-10-01T18:08:08.867

5 Is an argument in natural language as logically valid as in formal logic? 2019-02-18T21:39:06.473

4 Is it possible to show that something does not exist? 2013-11-15T13:15:20.483

4 Help with simple deductive proof 2014-07-04T03:00:53.423

4 help with deductive proof 2014-08-30T17:33:41.333

4 How to deal with ¬∃ (negated existential quantifier) in a proof? 2015-08-24T20:45:39.853

4 How to find redundant premises? 2015-08-31T21:29:19.787

4 Proving the negation of universal quantification 2015-09-05T14:05:04.423

4 Where can I learn about the philosophy behind mathematical and logical proofs? 2015-10-16T18:28:43.357

4 Propositional Logic: How to prove the contraposition in the Fitch system? 2016-10-07T22:25:47.243

4 Is there any difference of terminology between a person who would never worship God and one who will upon proof? 2017-03-16T14:20:02.810

4 Is it provable that epistemically possible (possible for all I know) does not imply possible? 2017-03-24T20:39:14.160

4 Mill's Proof and Nozick's Experience Machine 2017-04-21T19:21:15.033

4 Do α and β entail each other? 2017-12-06T03:36:15.873

4 Proof Using Model Universe 2019-09-29T23:35:42.650

4 How to show (in a hand waving manner) that the Godel sentence is true 2019-12-24T16:15:18.917

4 Does software exist to automatically validate an argument? 2020-12-20T14:26:17.073

3 Is illogical = not logical? 2011-08-17T03:47:38.113

3 Can we add to PA a new predicate T such that for every sentence A of the old vocabulary the new theory proves T(Godel numeric number of A) iff A 2013-06-05T12:50:29.110

3 Prove P v ~P using most basic rules? 2013-09-29T21:51:52.643

3 Testing the validity of syllogism argument 2014-09-30T22:32:35.257

3 Help with a proof for the following arguments 2014-10-29T04:19:46.283

3 How to discharge an assumption? 2014-10-30T04:16:58.973

3 Does a statement exist which is its own proof? 2014-11-29T03:07:37.293

3 Are analogical middle terms sufficient for a valid demonstration? 2015-01-23T03:56:43.033

3 Help with a proof in Classical Sentence Logic 2015-02-12T18:39:13.527

3 Prove A ∨ D from A ∨ (B ∧ C) and (¬ B ∨ ¬ C) ∨ D ( LPL Q6.26) without using --> or material implication 2015-02-22T19:26:06.007

3 What's the difference (if any) between demonstration and description? 2015-07-17T22:47:18.377

3 A and ~A in logical proof 2016-05-28T03:12:05.777

3 How would one go about proving the following statement in predicate logic? 2016-11-29T08:54:04.347

3 New riddle of induction; does the observer know the arbitrary time t? 2016-12-18T06:30:25.800

3 What is the relationship between the BHK interpretation of propositional logic and Natural Deduction? 2017-03-14T12:18:41.117

3 Can there be true conclusions without assumptions? 2017-04-27T05:08:30.437

3 Use the Fitch system to prove the tautology (p ∨ ¬p) 2017-05-09T01:12:21.343

3 How does one prove a generalised conditional statement? 2017-07-28T15:50:19.403

3 Does anyone know of a philosophy which rectifies or considers the following question? 2017-12-15T05:36:41.120

3 Can any correct logical reasoning in natural language sentences be translated into a formal mathematical proof? 2018-05-12T21:17:13.910

3 Is there a way to prove the existence of choice and free will 2018-05-12T22:40:51.960

3 Symbolic Logic - Negation Introduction 2018-06-18T22:05:31.493

3 2 simple Formal Fitch Proofs 2018-10-08T01:44:03.673

3 Can results be predicted? 2018-11-16T11:37:48.417

3 How to prove ‘∃xP(x)’ from ‘¬∀x(P(x)→Q(x))’ 2018-11-25T19:56:56.143

3 Do picture proofs of the Pythagorean theorem make it empirical? 2019-02-13T22:39:52.240

3 How to Prove P(a) → ∀x(P(x) ∨ ¬(x = a)) using Natural Deduction 2019-04-02T23:56:40.170

3 How to find a stance towards a controversial topic 2019-05-09T10:58:04.017

3 Deductive argument in which every step and premises are explicitly stated? 2020-05-09T15:40:34.477

2 Underlying logical structure behind Descartes' Ontological argument? 2011-12-22T01:24:33.660

2 Negative facts and truths 2012-11-16T00:51:30.640

2 I've confounded myself with this formal logic "proof" 2013-03-14T18:04:28.917

2 Prooving ( ∃x Fx ∨ ∃x ~Fx) from no premises 2013-11-04T02:31:08.710

2 Showing b=a from a=b in Fitch Style System 2013-11-20T03:22:42.697

2 showing c=a v b=c from a=c v b=c? 2014-05-11T18:29:12.190

2 Help with a modal Hilbert-style proof of (□(a>b)&◊(a&c))>◊(b&c) 2014-07-03T13:10:58.027

2 How does one contradiction in argument makes the argument valid? 2014-10-19T07:35:03.907

2 An argument is valid if the premises CANNOT all be true without the conclusion being true as well 2014-11-08T02:00:28.783