28 Mr Wiener, Studies in Synthetic Logic. * 
i. 
If we want to secure the compactness of int‘P, it is sufficient 
to assume the compactness of P,,|P, though not, as far as I know, 
necessary. Similarly, P,.|Pe¢Ded is a condition sufficient to 
assure the Dedekindian character of int*P. ¢ 
The interest and importance of this work on sensation-inten- 
sities lies in the fact that it is often naively assumed by psycho- 
logists that the series of sensation-intensities is in some wise | 
a datum of experience, and not a construction. As a result, they | 
are led into the most grotesque interpretations of such numerical) 
formulae as Weber’s law. A series of sensation-intensities is | 
often treated as if it were, in some sense or other, a series of) 
sensation-quantities, without any analysis whatsoever of the basis | 
on which this series is put into one-one correspondence with the | 
series of 0 and the positive real numbers, in order of magnitude. 
It is at any rate a necessary preliminary to this exceedingly | 
complex problem to know what the series of sensation-intensities 
really are, and what their relation to our experience is: with- 
out this analysis, no scientific psychophysics is possible. 
i 
