It is worth mentioning the interesting paternity of an 
insight that works its way from Ludwig Mises, to Friedrich 
Hayek, to Karl Popper, and finally into the work of Thomas Kuhn. 
As far as I can trace, the fairly clear recognition of the 
many-many problem of perception and observational classification 
which blocks reduction to 'physical categories' is found first 
in Mises, in his _Epistemological Problems of Economics_, and then 
next can be found in Hayek's essay "Scientism and the Study of 
Society", and then, with a citation to Hayek, in Popper's "The Bucket and the  
Searchlight", and then, finally, in Kuhn's "Second Thoughts on Paradigms." 
Perhaps the most indept discussion of this many-many problem is found 
in Hayek's _The Sensory Order_, but its significance for epistemology and 
the theory of science is perhaps best conveyed by Kuhn: 
 
".. people do not see stimuli, our knowledge of them is highly  
theoretical and abstract .. much neural processing takes place between 
the receipt of a stimulus and the awareness of a sensation.  Among 
the few things that we know about it with assurance are:  that very  
different stimuli can produce the same sensations; that the same 
stimulus can produce very different sensations; and, finally, that the 
route from stimulus to sensations is in part conditioned by education. 
Individuals raised in different societies behave on some occasions as 
though they saw different things.  If we wer not tempted to identify one- 
stimuli one-to-one with sensations, we might recognize that they  
actually do .. None of this would be worth saying if Descartes had been 
right in positing a one-to-one correspondence between stimuli and 
sensations.  But we know that nothing of the sort exits.  The preception 
of a ginve color can be evoked by an infinite number of differently 
combined wavelengths.  Conversely, a given stimulus can evoke a variety 
of sensations, the image of a duck in one recipient, the image of a 
rabbit in another.  Nor are responses like these entirely innate.  One 
can learn to discriminate colors or patterns which were indistinguishable 
prior to training." 
 
 
Greg Ransom 
Dept. of PHilosophy 
UC-Riverside 
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