Stanford, California - Quite a few people in Australia, the United Kingdom and the United States are looking online for information about Kantian morality. And the relationship between education and philosophy is piquing the interest of web surfers worldwide.

How do we know this? The data comes from the Stanford Encyclopedia of Philosophy, the web's oldest and arguably most credible open-access source of philosophical information.

Launched two decades ago, years before Wikipedia existed, the site led the way in academic information sharing. It now includes 1,478 authoritative and vetted entries about all manner of philosophical topics. It is updated almost daily, thanks to about 2,000 contributors.

The encyclopedia averages more than a million Internet hits per week. Users include students, scholars, librarians and even military officials.

Due to its alternative scholarly publishing model – the encyclopedia is free and edited by experts – the SEP is one of the few of its kind.

"There was just no model for this, a reference work that was revisable where all the scholarly standards were maintained," said Stanford's Edward Zalta, the executive editor of the site and a senior research scholar at Stanford's Center for the Study of Language and Information. The encyclopedia is one of the leading resources for scholarly research, Zalta said.

Zalta, a scholar of metaphysics and philosophy of mathematics, designed the site after discussions with Stanford philosophy Professor Emeritus John Perry. His concept for a dynamic encyclopedia grew out of Perry's suggestion for a static dictionary of philosophy.

Widespread support

Perry said he had something more modest in mind at the time: the organization of content already online. He did not expect that Zalta would be able to gain the support of members of the profession to edit and write as extensively as they have.

"For me, as with most philosophers nowadays, I think, the SEP is the go-to reference work in philosophy," Perry said.

Scholars from fields as diverse as architecture, drama, music, neuroscience, psychology and mathematics regularly turn to the site for information.

But the widespread non-academic usage of the site is perhaps even more remarkable. "If you're a member of the public, you have the greatest chance of interacting with philosophy via the SEP than via any other academic project," Zalta said.

Entries are regularly cited in law briefs and court cases both in the United States and in Europe, Zalta said. The site was also read and referenced in military contexts more than 15,000 times between September 2013 and September 2014.

Zalta recalled getting an email from an army chaplain in Iraq who wanted to assign the encyclopedia entry on "War" for reading by soldiers. He was particularly interested in the section on "Just War Theory" in the course he was teaching for the troops.

"The theory, in part, states that you should fight if and only if the war is just. If the cause is not just, you're not supposed to launch a war. This is the principle that philosophers have found compelling, which the article goes into," Zalta said.

Beyond crowdsourcing

The SEP boasts an editorial board made up of scholars vetted by its central advisory board. The executive editors in consultation with the editorial board are responsible for soliciting articles from authors as well as approving submitted entries from scholars.

Entry authors are expected to hold an accredited doctorate in philosophy or a related discipline and to have published refereed works on the entry topic. At least one subject editor from the editorial board or an appointed reviewer then referees each article and update before it is published.

Unlike Wikipedia, the SEP isn't a crowdsourced model. Instead, authorities from the academic philosophical community rigorously vet the content before it is published online, much like the peer review process of journals.

Writers and members of the editorial board see themselves as joining the SEP's team of authorities for the long term.

In fact, authors are expected to return to their articles and update them for years to come. This distinguishes the encyclopedia from many other academic publications.

"We see the SEP as a way of organizing people to produce and maintain this reference work, as opposed to a publication effort," said executive editor and research associate Uri Nodelman.

Finally, the encyclopedia allows users to quote and reference archived copy. As Zalta noted, this degree of authority and accountability would be impossible in a crowdsourced model where anyone can edit the articles and where the content can change too often to reasonably track.