What is Logic: Definition and 1000 Discussions

Logic (from Greek: λογική, logikḗ, 'possessed of reason, intellectual, dialectical, argumentative') is the systematic study of valid rules of inference, i.e. the relations that lead to the acceptance of one proposition (the conclusion) on the basis of a set of other propositions (premises). More broadly, logic is the analysis and appraisal of arguments.There is no universal agreement as to the exact definition or boundaries of logic (see § Rival conceptions). However, the scope of logic (broadly construed) includes:

The classification of arguments.
The systematic analysis of logical forms.
The systematic study of the validity of deductive inferences.
The strength of inductive inferences.
The study of faulty arguments, such as fallacies.
The study of logical paradoxes.
The study of syntax and semantics of formal languages.
The study of the concepts of meaning, denotation and truth.Historically, logic has been studied mainly in philosophy (since Antiquity), mathematics (since mid-19th century), and computer science (since mid-20th century). More recently, logic has also been studied in linguistics and in cognitive science. Overall, logic remains a strongly interdisciplinary area of study.

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  1. E

    Engineering Understanding Voltage Distribution in an Electrical Circuit Logic

    Trying to study in preparation for an exam, I've been told that I need to consider the circuits a little more. So in this circuit: Would the voltage across the resistor be the voltage across V0? Or would it be the voltage across the inductor because the capacitor is keeping the resistor...
  2. F

    Good Mathematical Logic Textbook?

    I've been trying to decide on a mathematical logic textbook to teach myself a bit. I'm taking a course on it next semester, but I have never had a logic course before (I've had some CS courses though and proof-y math courses). I'm also taking a modal logic course the semester after math logic...
  3. M

    Logic puzzle solution without guesswork?

    Here's the puzzle: http://9gag.com/gag/4137344 Now, I did this fairly quickly with the right tools(another use for excel found). However along the way I had to make 2 assumptions/random guesses: The yellow vs dunhill in houses 1 or 3 The dane vs tea in houses 2 or 5 Question being, can this...
  4. R

    MAking logic gates with 3-pin trasnistors

    I'm trying to make logic gates using MOSFET transistors, for a lab. for the prep, my lab group designed logic gates based on 4-pin transistors, but the MOSFETs we were provided with only have 3 pins. Is it possible to make logic gates using 3-pin trasnistors, and if so how?
  5. R

    Programs EE Majors: Should I take Electric Circuits or Digital Logic?

    I'll be taking a heavy workload of classes next semester. This will be the first time I'll be taking all technical classes. To ease my transition, should I take electric circuits or digital logic? What is the general consensus in terms of which one of these classes is more difficult?
  6. D

    Incredibly simple question about the logic behind systems of equations

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  7. binbagsss

    Quick logic question,SHM, second order differential equation

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  8. H

    How do physicists use redshift to determine the expansion of the universe?

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  9. H

    Proving \neg x \vee x in Hilbert System: A Logical Dilemma

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  10. X

    Making a Logic Circuit: Learn How to Build an OR Gate

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  11. A

    Meaning of this statement (logic)

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  12. A

    Intro to Logic: Constructing Proofs

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  13. J

    Newton's logic behind taking force as change in momentum w.r.t time?

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  14. Rasalhague

    Uncovering the Logic Behind Cl(A) = A

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  15. D

    Sequential Logic Design-State Diagram for a divider

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  16. N

    CMOS gate for the logic function

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  17. J

    Find the gain in a non-ideal op amp - check my logic

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  18. B

    Abstract math, sets and logic proof

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  19. R

    Sentential logic exercise from 'How to Prove it - A Structured Approach'

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  20. N

    Questions about the logic of infinity

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  21. L

    Help with indirect logic proof please

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  22. L

    Help with indirect logic proof please

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  23. Femme_physics

    Statics Mechanics: Looking for the flaw in my logic

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  24. G

    Max/Min in Calc III- Confused about relation between equations logic?

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  25. F

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  26. F

    [LOGIC] Proof by Induction in Peano Arithmetic

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  27. P

    Help me parse the logic of this statement

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  28. Femme_physics

    How to Draw Logic Gate Graphs for NOR and XOR Gates

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  29. E

    3 Input Majority Logic Circuit

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  30. B

    How does a logic gate permanently maintain its state?

    Logic gates can be switched to a high state, where the current flow is cutoff and a low state, allowing current to flow through. What electromagnetic processes in the semiconductor material enable this to happen? Since the switching action is purely electronic and there are no moving parts...
  31. C

    Logic - Logically equivalent

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  32. S

    Modern Classic Logic: A Comprehensive Guide to the Laws of Thought and Truth

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  33. A

    Engineering Differences between Logic Function and Logic Circuit

    Homework Statement The task required me to find the logic function / circuit for : a. comparator b. multiplexer c. adder d. register e. shifter So what are the differences between logic function and logic circuit? Thank you :) Homework Equations The Attempt at a Solution
  34. G

    Discrete Math Logic Defineing a function recursion-ish

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  35. T

    Geometry, logic and sun angles: help

    I am trying to figure out what size eaves we need for our house extension. I've tried a few calculations and now I'm posting here in the hope that a logical thinker will be able to tell me what I'm doing wrong. We live in Adelaide, Australia, and we want to put in glass double-doors on a...
  36. T

    Muons experiment, strange logic

    In the muons experiment the flow is measured at top of a mountain and at the base of the mountain. The velocity of the muons was calculated http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/muonex.html The velocity is 5 times the speed of light, which is of course against the relativity...
  37. H

    MHB Best Logic Textbooks for Advanced Learning

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  38. D

    Relativity: what's wrong with this logic?

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  39. P

    Proving Statements by Contradiction: Understanding the Logic Behind It

    Hi, I have a question about proofs by contradiction in general. Without getting into the mathematical details, suppose we had the statement: For every (condition A), B is true. If we want to prove this by contradiction, we want to assume the negation of this statement, and then prove it to...
  40. J

    Logic of quantified statements: for all vs if then

    Statement 1: If n is any prime number > 2, then n+1 is even. Statement 2: For all prime numbers p, if p>2, then p is even. The above two statements seam equivalent, but have different converses, etc. converse 1: If n+1 is even, then n is a prime number > 2. converse 2: For all prime...
  41. Saladsamurai

    Sentential Logic: Is the argument valid?

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  42. Femme_physics

    Logic Gates with XOR gate need to verify solution

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  43. N

    Difficult Predicate Logic Symbolization

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  44. F

    What are the steps for using natural deduction in logic?

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  45. Femme_physics

    What is the Simplification of a Boolean Function Using Karnaugh Maps?

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  46. S

    Did any of my classmates cheat on their homework?

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  47. K

    What does possibly necessary mean in modal logic [crazy question actually]

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  48. S

    Logic gates, inverting output without increasing transistor count

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  49. B

    Becoming proficient in Symbolic Logic

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  50. A

    Mathematical Logic, Interpretation, Satisfiable, Consequence relation

    Theorem : let A be a set of formulas, a be a formula For all A and all a, Every interpretation which is a model of A is also a model of a iff not (Sat A) U {~a} Proof Every interpretation which is a model of A is also a model of a iff(1) there is no interpretation which is a model of A but...
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