|A depiction of Isaac Asimov’s character Hari Seldon, by artist Michael Whelan (Ѻ), who, as mathematics professor at Streeling University on Trantor, develops “psychohistory”, a new science allowing him to predict the future in probabilistic terms, which he uses to predict the eventual fall of the Galactic Empire, hence his nickname "Raven" Seldon (see: Mor).|
Asimov, of note, has commented that the voice of Nat Schachner and his “Past, Present, and Future” (1937) (Ѻ) story, “sounded in his ear” several times when he came to write The Foundation Series.
In 1998, Gary Wolfe, in his “Stasis and Chaos” (Ѻ), was alluding to the suggestion that Hari Seldon, in Asimov's mind, was based on Henry Adams:
“In these seven years man had translated himself into a new universe which had no common scale of measurement with the old. He had entered a supersensual world, in which he could measure nothing except by chance collisions of movements imperceptible to his senses, perhaps even imperceptible to his instruments, but perceptive to each other, and so to some known ray at the end of the scale. Langley [Samuel Pierpont Langley] seemed prepared for anything, even for an indeterminable number of universes interfused—physics stark mad in metaphysics. Historians undertake to arrange sequences—called stories, or histories—assuming in silence a relation of cause and effect. These assumptions, hidden in the depths of dusty libraries, have been astounding, but commonly unconscious and childlike; so much so, that if any captious critic were to drag them to light, historians would probably reply, with one voice, that they had never supposed themselves required to know what they were talking about.”— Henry Adams (1908), An Education of Henry Adams (pgs. 381-82)
In recent years, some have conjectured that Heri Seldon was based on Henry Buckle:
“Buckle was the ‘Hari Seldon’ of his day, and much anger was directed at him by establishments who ruled superstitious and nationalist societies. Even Darwin, called "the most dangerous man in England" by priests, didn't provoke the level of hatred aroused by Buckle. That fear and hatred seems to persist even today in parts of the English establishment.”— Ray Dickenson (2000), “Notes on Henry Buckle: the First Scientific Analyzer of Social Evolution” 
“Buckle has been referred to as the ‘Hari Seldon’ of the 19th century.”— Tom Siegfried (2006), A Beautiful Math 
“At the other extreme lay the views of Henry Buckle, who, in History of Civilization in England, Volume 1 (1857), looked forward to the day when the power of statistics would forge laws of the social sciences and afford a comparable predictability to that acquired by physics through the use of mathematics. The future, of course, was to reveal that the truth lay in between the visions of Cournot (Ѻ) and Buckle. But even in the mid-twentieth century, the most famous of science fiction sagas, The Foundation Trilogy (1951-1953) by Isaac Asimov (January 2, 1920—April 6, 1992), predicted that a kind of social statistical mechanics applied on a galactic scale would eventually permit statistically significant forecasts of dominant social trends that lay hundreds of years in the future.”— Mark Rubinstein (2011), A History of the Theory of Investments (pg. #)
While difficult to find an actual statement by Asimov that he based “Seldon” on Buckle, some (Ѻ) have pointed out that both Asimov and Buckle were avid chess players. Generally, Buckle and his use of "statistics" to make his model of history, would seem more thematic to the Seldon character, than as compared to Adams and his "chemical thermodynamics" based history model.
The following are related quotes:
“Hari Seldon devised psychohistory by modeling it upon the kinetic theory of gases. Each atom or molecule in a gas moves randomly so that we can’t know the position or velocity of any one of them. Nevertheless, using statistics, we can work out the rules governing their overall behavior with great precision. In the same way, Seldon intended to work out the overall behavior of human societies even though the solutions would not apply to the behavior of individual human beings.”— Isaac Asimov (1986), “Explanation by character Janov Pelorat” 
“Hari Seldon is the intellectual hero of Isaac Asimov's Foundation series. In his capacity as mathematics professor at Streeling University on Trantor, he developed psychohistory (Ѻ), allowing him to predict the future in probabilistic terms. His ability to predict disasters is the reason behind his nickname ‘Raven’ Seldon.”— Anon (2019), “Hari Seldon” 
“Coming in at #1, in the polled ranking of the top ten most iconic sci-fi characters of all time, is Hari Seldon from Isaac Asimov's Foundation Series is your choice for most epic sci-fi character of all time. In his capacity as mathematics professor at Streeling University on the planet Trantor, Seldon develops psychohistory, an algorithmic science that allows him to predict the future in probabilistic terms. On the basis of his psychohistory he is able to predict the eventual fall of the Galactic Empire and to develop a means to shorten the millennia of chaos [see: transition state] to follow. The significance of his discoveries lies behind his nickname “Raven” Seldon. In the first five books of the Foundation series, Hari Seldon made only one in-the-flesh appearance, in the first part of the first book (Foundation), although he did appear at other times in pre-recorded messages to reveal a Seldon Crisis.”— Anon (2019), “The Most Iconic Sci-Fi Character of All Time” (Ѻ), Mar 21
1. Siegfried, Tom. (2006). A Beautiful Math: John Nash, Game Theory, and the Modern Quest for a Code of Nature (pg. 137). National Academies Press.
2. Hari Seldon – Asimov.Fandom.com.
3. Asimov, Isaac. (1986). Foundation and Earth (pg. 132). DoubleDay.
4. Dickenson, Ray. (2000). “Notes on Henry Buckle: the First Scientific Analyzer of Social Evolution” (Ѻ) (WB), Perceptions.couk.com.
● Hari Seldon – Wikipedia.