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Legal reasoning. – a continental approach and a common law approach. Aim:. use logical notions to describe a difference between a continental approach to legal reasoning and a common law approach to legal reasoning. Continental legal reasoning:. Basic idea:

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Legal reasoning

Legal reasoning

– a continental approach and a common law approach


Legal reasoning
Aim:

  • use logical notions to describe a difference between a continental approach to legal reasoning and a common law approach to legal reasoning


Continental legal reasoning
Continental legal reasoning:

Basic idea:

  • Having a general norm coded in a legal text we are constructing an individual norm that shall be applied in a particular case.

  • General norm: Every murderer shall be hanged.

  • Individual norm: John shall be hanged.


Continental legal reasoning1
Continental legal reasoning:

  • legal syllogism + legal subsuming


Continental legal reasoning2
Continental legal reasoning:

Legal syllogism:

 x ( P(x)  Q(x) )

P (a)

________________

Q(a)

Every murderer shall be hanged.

John is a murderer.

___________________________

John shall be hanged.


Continental legal reasoning3
Continental legal reasoning:

Legal subsuming:

K(a)  L(a)  ….  N(a)

____________________

P(a)

John took the knife.

John attacked Bill with the knife.

John caused Bill’s death.

________________________________________

John is a murderer.


Common law legal reasoning
Common law legal reasoning:

Basic idea:

  • If two cases are similar they shall be treated in a similar way.


Common law legal reasoning1
Common law legal reasoning:

  • legal analogy + legal distinguishing


Common law legal reasoning2
Common law legal reasoning:

Similarity:

  • At least one feature – identical.

  • At least one feature – different.

  • “abcde” and “abcde” are not similar (they are identical).

  • “abcde” and “abcdf” are similar.

  • “abcde” and “abcfg” are similar.

  • “abcde” and “afghi” are similar.

  • “abcde” and “fghij” are not similar (they are different).


Common law legal reasoning3
Common law legal reasoning:

Legal analogy:

K(a)  L(a)  ….  N(a)

Q(a)

K(b)  L(b)  ….  N(b)

___________________________

Q(b)

John took the knife. John attacked Bill with the knife. John caused Bill’s death.

John was hanged.

Jim took the knife. Jim attacked Dick with the knife. Jim caused Dick’s death.

_______________________________________________________________

Jim shall be hanged.


Common law legal reasoning4
Common law legal reasoning:

Legal distinguishing:

K(a)  L(a)  ….  N(a)

Q(a)

K(b)  L(b)  ….  N(b)

X(a)  Y(a)  ….  Z(a)

 X(b)  Y(b)  ….  Z(b)

___________________________

 Q(a)


Common law legal reasoning5
Common law legal reasoning:

YES:

John took the knife. John attacked Bill with the knife. John caused Bill’s death.

John was hanged.

Jim took the knife. Jim attacked Dick with the knife. Jim caused Dick’s death.

BUT…..


Common law legal reasoning6
Common law legal reasoning:

John was 25 years old. Bill was an innocent gay.

Jim was 12 years old. Dick was not an innocent gay – he tried to rape Jim.

___________________________________Jim shall not be hanged.


Analogy as composed of induction and deduction
Analogy as composed of induction and deduction

Analogy:

a  b (i.e. K(a) and K(b) )

Q(a)

_________________________

Q(b)


Analogy as composed of induction and deduction1
Analogy as composed of induction and deduction

  • The same result may be achieved by a composition of induction and deduction

  • 1 step:

    K(a)  Q(a)

    ____________

    K(a)  Q(a)

    (tautology of classical propositional calculus)


Analogy as composed of induction and deduction2
Analogy as composed of induction and deduction

  • 2 step

    K(a)  Q(a)

    ___________

    x ( K(x)  Q(x) )

    (non-complete induction)

  • 3 step

    x ( K(x)  Q(x) )

    ________________

    K(b)  Q(b)

    (dictum de omni)


Analogy as composed of induction and deduction3
Analogy as composed of induction and deduction

  • 4 step

    K(b)  Q(b)

    K(b)

    ____________

    Q(b)

    (modus ponens)


Common law legal reasoning as compared to continental legal reasoning
Common law legal reasoning as compared to continental legal reasoning:

Common law reasoning:

  • Simpler (no need for general rules).

    Continental reasoning:

  • More complicated (general rules – necessity of subsuming).


Common law legal reasoning as compared to continental legal reasoning1
Common law legal reasoning as compared to continental legal reasoning:

Common law reasoning:

  • Simpler (no need for general rules).

  • Non monotonic (additional presumptions may change the outcome).

    Continental reasoning:

  • More complicated (general rules – necessity of subsuming).

  • Monotonic (necessity of so called “functional interpretations of law”, i.e. interpretations that are in contradiction with the wording of the legal text but are supposed to be just)


Common law legal reasoning as compared to continental legal reasoning2
Common law legal reasoning as compared to continental legal reasoning:

  • Common law reasoning – based on the concept of similarity.

  • Continental reasoning – based on the concepts of general rules and deduction.

    THE END