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Reduction and Elimination in Philosophy and the Sciences

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Conclusion<br />

396<br />

From Topology to Logic. The Neural <strong>Reduction</strong> of Compositional Representation — Markus Wern<strong>in</strong>g<br />

Figure 3: a) Stimulus: one vertical red bar <strong>and</strong> one horizontal green<br />

bar. It was presented to a network with 32×32×4 oscillators. b) The<br />

two stable eigenmodes. The eigenvectors v1 <strong>and</strong> v2 are shown<br />

each <strong>in</strong> one l<strong>in</strong>e. The four columns correspond to <strong>the</strong> four feature<br />

layers. Dark shad<strong>in</strong>g signifies negative, gray zero <strong>and</strong> light shad<strong>in</strong>g<br />

positive components. c) The characteristic functions for <strong>the</strong> two<br />

eigenmodes.<br />

Oscillatory networks show how a structure of <strong>the</strong> cortex<br />

can be analyzed so that elements of this structure can be<br />

identified with mental concepts. These cortical states can<br />

be regarded as <strong>the</strong> thoughts expressed by some first order<br />

logic. They form a compositional semantics for such a<br />

logic. The cortical states can <strong>the</strong>mselves be evaluated<br />

compositionally with respect to external content <strong>and</strong> thus<br />

provide denotations. The approach formulated <strong>in</strong> this paper<br />

is biologically ra<strong>the</strong>r well-founded. It is supported by a<br />

rich number of neurophysiological <strong>and</strong> psycho-physical<br />

data <strong>and</strong> is underp<strong>in</strong>ned by various computer simulations.<br />

The eigenmode analysis of <strong>the</strong> network enables <strong>the</strong> reduction<br />

of <strong>the</strong> logical structure we encounter <strong>in</strong> thought to <strong>the</strong><br />

<strong>the</strong> topological organization of <strong>the</strong> cortex.<br />

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