If the Hitler wasn't into phrenology then why were the NSDAP measuring so many people's skull's?
Anthropometry/physical anthropology was the primary way biologists studied humans in the 1930s/40s, since the field of genetics did not really exist as we know it today.
The difference between scientific anthropometry and phrenology is analogous to astronomy vs astrology.
For much more detailed information on this, you can read about the history of physical anthropology here. In particular, sections XII and XVI in part 2 are relevant to the conversation, and the origins of phrenology and its opposition to scientific anthropology are touched upon in section VI of part 1:
https://aryan-anthropology.blogspot.com/p/revisiting-early-20th-century_11.htmlhttps://aryan-anthropology.blogspot.com/p/revisiting-early-20th-century_93.htmlAlfred Rosenberg also warned against strict reliance on anthropometry to determine an individual's worth:
"Nothing would be more superficial than to measure a man's worth by his physical appearance (with a centimeter rule and cephalic indices). A far more accurate measure of worth is conduct." - Alfred Rosenberg
So, on an individual level, measuring someone's skull is useless. But, aggregating individuals together on the population level _can be_ useful, since there is a correlation between the body's phenotype and the mind's phenotype. Even if the correlation is small, mathematically this means certain populations are, on average, more likely to have a given trait than others. In other words, skull measurements were used as a proxy for certain character traits, when applied to a population level, since there was no genetic testing back then (and even today the exact genes causing most personality traits have not yet been discovered).
I think skull measurements are less useful for science today since we have genetic testing. But studying the correlation between skull shape and character is useful in the aesthetic sense, since it is an easy way to demonstrate the fact that biological variation is meaningful. (I.e. National Socialist propaganda about "subhumans" was correct all along). Also, an individual's aesthetic preferences give us hints into whether that individual is likely to possess any correlated character traits (e.g. if they prefer Aryan-looking faces, are they more likely to possess Aryan personality traits with respect to ethical quality as well?)