Quantity Is A Quality Of Its Own

„Quantity has a quality all its own."

No evidence that this phrasing is due to Stalin, and it does not appear in English translations of his philosphical works. Earliest English is found in 1979 in US defense industry, presumably defense consultant Thomas A. Callaghan Jr. The connection of sufficient quantitative change leading to qualitative change is found in Marxist philosophy, by Marx and Engels, drawing from Hegelian philosophy and Ancient Greek philosophy. Marx and Engels are quoted by Stalin, but this formulation appears to be a modern American form; see quantity for details.
Stalin may have said that way before World War II, there is evidence in his Russian-language books, for example here http://www.modernlib.ru/books/stalin_iosif_vissarionovich/tom_14/read_16/.
Misattributed
Variant: Quantity is quality.
Source: Re: "Quantity has a quality all its own" source? http://h-net.msu.edu/cgi-bin/logbrowse.pl?trx=vx&list=h-russia&month=1004&week=a&msg=ljEwsM4dMrpmUGVfI7EGqg, Tim Davenport, h-russia https://networks.h-net.org/h-russia, April 5, 2010

Adopted from Wikiquote. Last update June 3, 2021.

Related quotes

„Color is primarily Quality. Secondly, it is also Weight, for it has not only color value but also brilliance. Thirdly, it is Measure, for besides Quality and Weight, it has its limits, its area, and its extent, all of which may be measured.Tone value is primarily Weight, but in its extent and its boundaries, it is also Measure.Line, however, is solely Measure."

— Paul Klee German Swiss painter 1879 - 1940

Quote from Klee's lecture 'On Modern Art', Kunstverein, Jena (26 January 1924), trans. Paul Findlay in Paul Klee: On Modern Art (London, 1948)
1921 - 1930

„When… we have a series of values of a quantity which continually diminish, and in such a way, that name any quantity we may, however small, all the values, after a certain value, are severally less than that quantity, then the symbol by which the values are denoted is said to diminish without limit. And if the series of values increase in succession, so that name any quantity we may, however great, all after a certain point will be greater, then the series is said to increase without limit. It is also frequently said, when a quantity diminishes without limit, that it has nothing, zero or 0, for its limit: and that when it increases without limit it has infinity or ∞ or 1⁄0 for its limit."

— Augustus De Morgan British mathematician, philosopher and university teacher (1806-1871) 1806 - 1871

Introductory Chapter, pp.9-10
The Differential and Integral Calculus (1836)

„The difference between the Jewish soul, in all its independence, inner desires, longings, character and standing, and the soul of all the Gentiles, on all of their levels, is greater and deeper than the difference between the soul of a man and the soul of an animal, for the difference in the latter case is one of quantity, while the difference in the first case is one of essential quality."

— Abraham Isaac Kook, book Orot

Orot Yisrael, Ch. 5, article 10, p. 156; as quoted in "The Distinction between Jews and Gentiles in Torah" by Rabbi David Bar Chaim http://www.daatemet.org.il/articles/article.cfm?article_id=119&lang=en
Variant:
The dissimilarity between the Jewish soul, in all its independence, inner desires, longings, character and standing vis-à-vis the soul of all the Gentiles — on all of their levels — is greater and deeper than the difference between the soul of a man and the soul of an animal, for the difference in the latter case is one of quantity, while the difference in the first case is one of essential quality
As quoted in "A British Synagogue Bans a Famous Hassidic Text!" (February 2010) by Rabbi Michael Leo Samuel http://rabbimichaelsamuel.com/2010/02/2744/#_ftn1.
Orot

„What we have to do is make progress in the quality of connection between people, not the quantity of consumption."

— Larry Harvey Founder of Burning Man 1948 - 2018

"The Wonderful, Weird Economy of Burning Man" in The Atlantic (18 August 2014) https://www.theatlantic.com/business/archive/2014/08/the-wonderful-weird-economics-of-burning-man/376108/
Context: We don't think the world can be Woodstock … Who'd think the world could be a perpetual carnival? But we do think that the world could rediscover values that used to be automatically produced by culture but aren't anymore because culture is subject to the commodification in our world. Everything is sold back to us, targeted to demographics. What we have to do is make progress in the quality of connection between people, not the quantity of consumption.