Researchers and historians may once again be turning to hyperspectral imaging to discover the true meaning behind one of America’s most iconic documents by resolving a bit of puzzling punctuation in the Declaration of Independence.

The hoopla is centered around the second sentence of the Declaration, in which some versions have a period after the iconic phrase “life, liberty, and the pursuit of happiness” and some don’t. (Instead they have a semicolon or a comma.) This makes a profound difference in its meaning, says the researcher who discovered the possible error and who has investigated what turns out to be many, many variations on the document.

“In its complete form, this sentence explains the relationship between individual rights and the value of government as a tool by which we, the people, collectively secure safety and happiness; moreover, it identifies this relationship as a matter of self-evident truth,” explains Danielle Allen, professor at the Institute for Advanced Study School of Social Science in Princeton, N.J., in her paper Punctuating Happiness. “When bi-sected with a period, however, the sentence designates as a matter of self-evident truth only the existence of human equality, as derived from our individual rights to life, liberty, and the pursuit of happiness. The question of how this sentence is punctuated, in other words, dramatically affects how we interpret the most important expression of American ideals written to date.”

(The 56-page paper is actually really interesting and has a lot of neat information about the writing and publishing of the Declaration of Independence and some of the word choices.)

The problem is, there’s no single definitive source. The official transcript of the U.S. National Archives, produced by an engraver named Stone, is what’s used as the definitive source by many people, but that’s the version that included and promoted the error, Allen writes. And the engrossed Congressional parchment version on exhibit in the National Archives Museum in Washington, which wasn’t created until 1791, is too hard to read at this point. So Allen set out to look at all the various versions of the Declaration that she could find.

Allen notes that there are, in fact, eight manuscript copies of the Declaration, created before and during its approval in 1776: six by Thomas Jefferson, who is considered to be the primary author; one by John Adams, who was also on the committee; and one by the secretary to the Continental Congress.

There was inconsistency from the start, as these eight copies don’t agree on matters such as punctuation and capitalization, Allen writes. But they do agree on one thing: “Not one of these manuscripts by Adams, Jefferson, or Thomson employs a period after ‘pursuit of happiness,’” she notes. “All of them render the second sentence of the Declaration as a single sentence.”

So what is Allen’s explanation for why some copies have a period? An inkblot? A dead fly? No, it stems from Jefferson’s habit of putting little marks in the text of things intended to be delivered as speeches, to indicate where the speaker should pause for emphasis. One of the first printers to publish the Declaration mistakenly read one of those marks to be a period, and he typeset it as such, she contends. Moreover, because Adams himself—who edited that printer’s version—had been a proponent of the phrase “life, liberty, and the pursuit of happiness,” he would have been fine with leaving in the period, because it called attention to his work, she writes.

Allen also looked at more than 70 different versions of the Declaration written and printed by various people, discussing which ones had the period, which didn’t, and why. Most notably, she writes about the official, engrossed version of the Declaration, written on parchment on July 19 by the secretary’s clerk, Timothy Matlack. That copy, which is old and faded, may have a period, or it may have a comma, and Allen goes to great lengths to explain why she believes it’s a comma and not a period. She also notes several other instances in other printings where commas were turned into periods.

As with documents such as the Archimedes Palimpsest, Allen exhorts scholars to call for hyperspectral imaging on the 1791 Matlack parchment version of the Declaration to see whether the question can be settled one way or another. “There is a high probability that the parchment of the Declaration has not been clearly legible since sometime between 1805 and 1817,” she writes, citing that as a possible reason for the various transcription errors—more than just the period. “Since the parchment has not in fact been read in so long, and since we now have a tool with which we could once more actually read it, should we not perhaps attempt to do so?”

Such hyperspectral imaging may be possible, William A. Mayer, executive for research services at the National Archives, told the New York Times (where an article on Allen’s research received more than 200 comments). However, he implied that any such imaging would need to be done through the glass in which the parchment is housed.

It wouldn’t be the first time. In fact, Jefferson’s rough draft of the Declaration was already subject to hyperspectral imaging in 2010, though the descriptions of it at the time don’t mention whether it used a period after “happiness.”

Perhaps there’s time to get it done by next Fourth of July?

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