Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the...

35
                                                                                       

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Abstract: The paper attempts to show how the Logical Empiricists’ interpretation of the relation between geometry and reality emerges from a “collision” of mathematical traditions. Considering Riemann’s work as the initiator of a 19th century geometrical tradition, whose main protagonists were Helmholtz and Poincaré, the Logical Empiricists neglected the fact that Riemann’s revolutionary insight flourished rather in a non-geometrical tradition dominated by the works of Christoffel and Ricci-Curbastro roughly in the same years. I will argue that in the attempt to draw the line Riemann-Helmholtz-Poincaré-Einstein Logical Empiricists were led to argue that General Relativity raised mainly a problem of mathematical under-determination, i.e. the discovery that there are physical differences that cannot be expressed in the relevant mathematical structure of the theory. However, a historical reconstruction of the alternative line of development Riemann-Chritoffel-Ricci-Einstein shows on the contrary that the main philosophical issue raised by Einstein’s theory was rather that of mathematical over-determination, i.e. the recognition of the presence of redundant mathematical differences that do not have any correspondence in physical reality

Transcript of Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the...

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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 n  

 

 n    x1, x2, x3, . . . , xn

 

     

 

ds  

  dx  

  x

 

 

 

 

 

 

n  

  n  

x1, . . . xn  

 

 

ds2

 

 

 

 

 

 

 

 dx2

 

 

 

 

 

 

 

 

 

 

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ai,idxidxi

  ai,i  

dx2

i  

  xi    i  = 1, 2, 3)

 

 

 

 

 

(ιι

, ι

ι

)  

  ai,i    xi  

 

(ιι, ιι)= 0  

 

  ai,i  

 

 

 

 ι,ι bι,ι dsι dsι  

 n  

 

 

 

 

 

bι,ι dsι dsι  

 

ι

d2ι

 

 

 

 

 

  (s1, s2, . . . , sn)

 

 

 

     

     

 

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7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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  F   =

ωikϑxiϑxk   F  =

 ω

ikϑx

iϑx

k  

 

 

  ωik  

∂ωgk

∂xh  

 

ghk

 

  ilr

 =

 E rkE 

ghk

 

 

 

  (ghki)  

 

 

ωik  

     

  (ghki)    (ghki)

 

 

 

     

 

 

 

 

 

 

  n

 

 

 

 

 ϕ   =

 rsarsdxrdxs    ars  

 

x1, x2, . . ,xn  

 

  x1, x2, . . ,xn  

u1, u2, . . ,un  

  ϕ =  ϕ

 

ErkE

   ωik

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  ars  

  (a pq)  

 

a

(rs)  

a

( pq)  

  ars    a(rs)  

 

  ars,i

  ahi,jk  

 

   

   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

   

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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ds2 =

gµν dxµdxν   

 

 

  gµν   

 

 

 

  δ ´ 

 ds

= 0

 

 

gµν   

 

 

∂ 2ϕ∂x2   +   ∂ 2ϕ

∂y2   +   ∂ 2ϕ∂z2   = 4πkρ

  gµν   =  gνµ    ϕ  

  ρ    Θµν   

  Γµν 

 

gµν   

 

 

  κ ·Θµν  = Γµν     κ

 

  (ik,lm)  

 

 

 

 

 

 

 

      ∆φ  

 

 

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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d2xτ 

ds2  =µν 

  µν 

τ 

dxµ

ds

dxν 

ds

 

 

  gµν     T µν 

   

 

 

 

 

 

 

 

   

 

 

  Rµν   

  T µν   

  Gµν  = Rµν − 12Rgµν     R =  gµν Rµν  

  Gµν   

 

Gµν   = −κT µν   

 

 

gµν

 

 

  gµν    T µν

  gµν(x)    gµν (x)

 

x  

  x  

  gµν(x)    gµν(x)    x

 

 

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  Γτ µν  = −

  µv

τ 

 

  gµν     Γτ µν  = 0  

  gµν   

  Γτ µν  = 0  

 

 

     

 

 

Γτ µν     Rρ

µντ 

 

 

Rρµντ   

 

 

 

  gµν   

 

gµν   

 

 

 

 

gµν   

 

ds2

 

 

 

   

 

 

 

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d2xτ 

ds2

  = Γ

τ 

µν 

dxµ

ds

dxν

ds  

 

 

   

 

  gµν     Γτ µν 

 

 

 

 

 

 

 

 

 

 

  gµν     Γτ µν   

 

 

 

     

 

gik    Γihl  

 

 

 

 

 

 

 

 

  Γihl    gik

 

 

 Γihl  

 

 

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  Γisr  = Γi

rs      

 

 

 

 

     

 

 

 

 

 

 

   

   

 

 

 

   

 

 

  Γikl

 

 

  Γikl  

  gik

 

 

 

 

 

 

 

 

 

 

 

 

 

   

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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ds2 =4

Σ1

dx 2ν   

 

 

ds2 =4

Σ1

gµν dxν dxν 

 

gµν

 

 

 

 

 

     

   

   

 

 

  gµν   

 

  gµν   

     

 

   

 

  gµν   

 

 

 

 

gµν  

     

 

 

       

   

gµν  

 

 

 

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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gµν   

  gµν   

 

       

 

gµν    

 

 

  gµν  

 

 

   

 

 

 

  gµν   

 

     

 

gµν   

 

     

   

     

 

 

 

   

   

 

 

   

 

     

 

 

 

 

   

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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P     

 

 

 

  G + P 

 

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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  X   

 

 

 

X   

  X   

 

  X   

 

 

X  = 0  

 

 

 

 

  X 

 

 

 

 

  gµν  

 

ds2 =

dx2ν      

 

 

gµν  

   

 

gµν  

 

ds2

 

 

   

 

 

 

 

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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      gµν     

   

 

 

 

 

gµν   

 

 

  gµν   

 

   

 

 

∂gµν∂xσ

 

 

 

∂ 2gµν∂xσ∂xρ

 

 

 

   

 

   

     

 

 

 

 

 

 

 

       

 

     

 

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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F   = 0  

  G

 

 

 

 

  θ    G  

  G   F   

 

G +  F   

 

F  = 0

 

  G  

  G  

         

   

  F   

 

 

 

 

 

 

 

 

  gµν 

  gµν           

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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gµν   

 

 

  gµν   

 

  gµν   

ds2  

  g

µν   

 

gµν   

 

  gµν   

 

 

gµν  

 

 

     

   

   

 

g

µν  

 

x

µ  

 

  gµν  

 

g

µν  

 

ds2

= gµνdxµdxν   = g

στ dx

σdx

τ 

 

ds2

 

 

gµν  

 

 

 

 

  (1,  1)  

√ 2,   π/4  

 

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  gµν   

  gµν   

  F.

 

F   

  g

µν  

  G   gµν    G    F µν    F   

 

g

µν   + F µν   = gµν  

  g

µν

 

F µν  

  g

µν  

 

gµν  

  F   

 

g

µν   

  F µν   

  gµν    ds2 =   gµν dxµdxν   = (g

µν  +F µν )dx

µdx

ν     gµν   

    g

µν   

 

  ds2 = gµν dxµdxν  = g

µν dx

µdx

ν   

  gµν     

  g

µν   

 

  ds2  

 

       

 

 

 

 

   

 

 

     

 

 

 

 

     

      gµν   

 

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gµν  

 

gστ   

 

gµν    

       

gµν      

     

 

  gµν   

     

 

  gµν     g

µν     ds2 =   ds2  

 

 

 

 

 

 

gµν  

  gµν

∂gµν∂xσ

∂ 2gµν∂xτ ∂xσ

 

Rµνστ 

  Rµνστ 

 

 

  Rµνστ   

 

Rµνστ   = 0

Rµνστ   

 

Rµνστ     gµν .  

  gµν   

  gµν   

  Γτ µν   

gµν   

 

gµν     Γτ µν   

  gµν   

 

 

   

 

 

 

     

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  K   

  g

στ   

 

K   

  gµν 

   

   

gµν   

  K  

 

  K 

  K 

  g

στ     gµν   

 

   

 

    gµν    

  Γτ µν   

 

 

   

     

   

 

 

 

  gµν 

 

 

 gµν   

     

 

   

 

gµν   

 

 

 

 

gµν  

 

gµν  

  Γτ µν  

∂gµν∂xτ 

  Γτ µν

 

 

 

gµν  + γ µν  

  gµν  

gµν  

  gµν  

     

γ µν

  Γτ µν    γ µν  

gµν  

 

 

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  Γτ µν   

 

   

 

 

 

 

gµν       

 

 

∂gµν∂xτ 

 

  g44  

 

 

 

 

gµν   

  g

στ   

   

 

 

 

 

 

 

Rµνστ   

 

     

 

     

   

 

 

 

 

     

   

 

   

   

   

 

   

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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  gµν     

 

   

 

 

 

gµν       

 

 

  gµν   

 

   

 

 

 

   

 

  Γτ µν   

 

   

 

Rµνστ 

 

     

     

 

 

 

 

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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  Γτ µν (xν   

  gµν (xν )  

 

 

 

 

 

     

 

   

 

 

 

  Γτ µν     gµν   

 

   

     

dAτ  = −Γτ µν A

µdxν   

     l2 =   gµν AµAν 

 

 

 

 

 

     

 

 

 

  Γτ µν   

 

  gµν   

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Γlik    Riklm  

 

 

 

 

gik  

 

Γlik  

  P   

  P    δAν= −Γ

νστ A

σdxτ  

 

 

gik  

 

 

 

 

 Γ  

 

Riklm  

  Rkl  

 

 

 

 

 

 

 

     

 

 

 

     

 

 

 

     

 

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

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 gµν   

 

 

 

 

 

 

 

 

 

 

   

 

 

     

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

http://slidepdf.com/reader/full/giovanelli-marco-2012-the-forgotten-tradition-how-the-logical-empiricists 31/35

 

   

   

 

     

 

 

   

 

   

 

   

 

     

 

       

 

     

   

     

 

     

 

   

 

   

 

 

     

   

     

 

       

 

 

   

 

   

 

     

     

   

 

 

 

   

   

 

 

     

     

   

 

   

 

     

 

 

   

     

   

 

     

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

http://slidepdf.com/reader/full/giovanelli-marco-2012-the-forgotten-tradition-how-the-logical-empiricists 32/35

 

 

     

   

 

     

 

     

     

     

   

 

 

 

   

 

 

     

   

 

 

 

 

 

   

 

 

     

 

 

     

 

 

 

     

 

 

 

   

 

 

   

     

 

   

   

   

   

     

 

     

   

 

     

   

   

     

 

   

   

 

   

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

http://slidepdf.com/reader/full/giovanelli-marco-2012-the-forgotten-tradition-how-the-logical-empiricists 33/35

 

 

   

     

     

 

     

 

 

     

 

 

     

 

 

 

         

   

   

 

   

 

     

     

   

 

 

     

 

 

   

   

 

     

   

 

 

     

     

     

 

 

   

 

 

     

 

     

   

 

   

 

     

 

 

     

     

 

   

 

   

 

 

   

 

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

http://slidepdf.com/reader/full/giovanelli-marco-2012-the-forgotten-tradition-how-the-logical-empiricists 34/35

 

   

 

 

     

 

   

     

   

 

     

   

     

 

   

     

   

     

 

     

   

   

   

 

 

   

 

     

 

   

   

 

 

   

   

 

 

   

 

   

   

   

     

   

 

 

 

   

   

 

 

     

 

   

 

   

 

   

 

     

       

 

 

 

       

7/18/2019 Giovanelli, Marco (2012) the Forgotten Tradition. How the Logical Empiricists Missed the Philosophical Significance …

http://slidepdf.com/reader/full/giovanelli-marco-2012-the-forgotten-tradition-how-the-logical-empiricists 35/35