Joe,

The Children's Theatre on the Lower East Side of New York is a
possible point of contact between Twain and John Dewey. Alice Herts,
its director, mentions Dewey's work in her book about the theater:

"Our recent pedagogy has not been insensible of the great losses
suffered by the child through the change in our civilization from one of
rural type to one of urban type; but it has had its eye chiefly on the so-
called manual activities of the child -- that side of the old life of the
child
on the farm or in the small semi-rural town, to which Professor Dewey
and his disciples have drawn our attention. They have insisted upon the
practical recognition of the principle of self-activity and the fundamental
motor-nature of the child. The child learns by doing, by trying, and we
must give back to him in new forms the old opportunity for instructive
activity which he had by doing things about the home and the farm."

http://www.boondocksnet.com/editions/herts/herts12.html

Twain was president of the theater's board of directors and was quite
active with it in 1907-1908. Was Dewey named as a guest at the benefit
performance of "The Prince and the Pauper" Twain organized in
November 1907? If not, he might have been there but wasn't prominent
enough at the time to be mentioned in the newspaper reports.

It is also possible that Twain had contact with John Dewey through their
association with the People's Lobby. Twain was a member of its
executive committee when it was formed around 1906. Among others
involved at that time were Ben B. Lindsey, Vance C. McCormick, John
Mitchell (AFL), Lincoln Steffens, and Brand Whitlock. Dewey was later
president of the organization but I don't know if their involvements
overlapped (I suspect Dewey's was later).

Dewey was also involved with the Anti-Imperialist League. He was active
in Chicago in the early 1900s while Twain was active in New York.
Dewey moved to New York in 1904. The Anti-Imperialist League of New
York was no longer active by that point. In 1910, Dewey succeeded
Twain as one of the national Anti-Imperialist League's vice presidents
from New York.

Jim