This question illustrates one of the pitfalls of “public access information.” While the Internet has brought vast knowledge to one’s fingertips, some of it is erroneous, and much of it is not sourced.
For example, the quotation “Some men see things as they are and say, why; I dream things that never were and say, why not” is often attributed to Senator Robert F. Kennedy. This quotation paraphrases the original lines authored by George Bernard Shaw: “You see things; and you say ‘Why?’ But I dream things that never were; and I say ‘Why not?’” These lines are said by The Serpent to Eve in the Garden of Eden in Shaw’s little known play, Back to Methuselah, published in 1921 and first performed in 1922. All three Kennedy brothers, John, Robert and Edward, said or paraphrased these lines at one time or another. For a reliable source, see bartleby. com http://www.bartleby.com/73/465.html
As for the “Parable of Immortality,” Dallas Public Library staff concurs with the folks over at the Transylvanian Dutch website for genealogy and family history. After 10 years of research, they believe that the Rev. Luther F. Beecher wrote the poem, which is also known as “What is Dying”. More details at http://blog.transylvaniandutch.com/2013/01/poetry-friday-what-is-dying-luther-f.html.
A cousin of Henry Ward Beecher, the Rev. Luther F. Beecher was a New England preacher. He died November 5, 1903 at nearly 91 years of age. Within the following year, at least three publications credit the poem to Luther Beecher: Northwestern Christian Advocate, July 13, 1904; Religious Telescope, Vol. 70, August 21, 1904; and Attica Daily Ledger, October 26, 1904.
Dallas Public Library staff is here to assist in finding reliable sources and quotations.
The Poem –
I am standing upon the seashore.
A ship at my side spreads her white sails to the morning breeze
and starts for the blue ocean.
She is an object of beauty and strength,
and I stand and watch until at last she hangs
like a speck of white cloud
just where the sea and sky come down to mingle with each other.
Then someone at my side says,
“There she goes!”
Gone from my sight . . . that is all.
She is just as large in mast and hull and spar
as she was when she left my side
and just as able to bear her load of living freight
to the place of destination.
Her diminished size is in me, not in her.
And just at the moment
when someone at my side says,
“There she goes!”
there are other eyes watching her coming . . .
and other voices ready to take up the glad shout . . .
“Here she comes!”