The Original Eliza(s)

(See other versions on the "Other Eliza-Like Programs" page.)

Joseph Weizenbaum's original article:

Weizenbaum, J. (1966) ELIZA - A computer program for the study of natural language communication between man and machine. CACM 9(1) 36-45.

[1966 Weizenbaum's original Eliza article in the CACM]

The paper remains under ACM copyright, and so is inaccessible except to members. However, Google Scholar lists numerous version of the PDF online. (Use keywords: weizenbaum eliza, and click on the "All ... versions" link below the extract. Then just pick your favorite PDF source.) I have confirmed that there are at least 15 copies that can be accessed by this route.

Bernie Cosell's Lisp Eliza @ BBN c. 1966-1972:

This is the original Lisp Eliza (aka. Doctor) program, written by Bernie Cosell based upon Joseph Weizenbaum's original work. Weizenbaum's wrote his program in SLIP, a long-dead Fortran-based symbolic computing package. Cosell, working at BBN, created this BBN Lisp version from Weizenbaum's paper (see above), not from the SLIP code. Nevertheless, as SLIP never saw the popularity of Lisp, this is the version of Eliza that most folks have used, and from which most lisp-based Elizas derive. (A separate BASIC fork, not based upon either the Lisp or SLIP versions, was popular on early PCs. See below.)

Bernie writes: "I *never* saw any of the SLIP code and knew nothing about it. I wrote Doctor *completely* working just from the CACM article! In fact, if the SLIP code actually surfaced, it'd be interesting to see how different/similar ours were, since I [really] never saw any of Weizenbaum's code. Truth is that I did Doctor as a learning hack. Dan Murphy was [and still is] a good friend of mine from MIT and he was working on bringing up Lisp on the PDP-1b in the other building at BBN while I was system-czar for the Hospital Timesharing system on our PDP-1d. I knew a little Lisp from a course at MIT, but I figured that the best way to really "get" Lisp was to write something real. I had just joined the ACM [I started at BBN in the fall of '65] and I think Weizenbaum's Eliza article just happened to be in the very first copy of Communications that I received."

This release include high resolution TIFF scans of printouts of Bernie's code, including the Lisp code and scripts. from 1969 and 1972. He also provided a paper tape version from 1966, which I am in the process of reading, and will make public soon. The release also includes combined OCRed PDFs of each program and script. The OCR is not very accurate. I intend to release perfect transcripts as well as Modern Lisp macros that make this work.

Eliza/Doctor in Lisp by Bernie Cosell

Licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

[20131112] 600dpi scans of 1969 and 1972 printouts combined into PDFs and (roughly) OCR'ed

[20131112] 600dpi raw scans of the printouts of BBN Lisp Eliza code and scripts from 1969 and 1972


We have made the 1969 version of Eliza (aka. Doctor) work on modern Common Lisp, having to change almost nothing in the raw code transcripts! Here is the GitHub repo containing the code. Thanks to the following folks who helped transcribe the code from the original printouts: eMBee, Dave Cooper, Bob Felts, Saul Good, Ben Hyde, Simon Leinen, Patrick May, Charlie McMackin, Paul Nathan, Matt Niemeir, Peter De Wachter, Thomas Russ, Patrick Stein, and Jeff Shrager. And these folks made it work in modern CL Peter De Wachter, Matt Niemeir, and Jeff Shrager. If you want to become a github collaborator and work hands-on this project, write Jeff Shrager (

Thanks to Peter Seibel for making the original connection to Bernie.

James Markevitch has read and translated the 1966 version of Eliza in BBN lisp, and has created an emulator (in PERL!) for it that results in a working version! It's all available on the github site, and also as a tarball here.

2014-12-20: Jeff Barnett writes:

The original Eliza was moved to the ANFS Q32 at SDC (one of the (D)ARPA block grant sites) in the mid 1960's. The programmer responsible was John Burger who was involved with many early AI efforts. Somehow, John talked to one of the Playboy writers and the next thing we knew, there was an article in Playboy much to Weizenbaum's and everybody else's horror. We got all sorts of calls from therapists who read the article and wanted to contribute their "expertise" to make the program better. Eventually we prepared a stock letter and phone script to put off all of this free consulting.

The crisis passed when the unstoppable John Burger invited a husband and wife, both psychology profs at UCLA, to visit SDC and see the Doctor in action. I was assigned damage control and about lost it when both visitors laughed and kept saying the program was perfect! Finally, one of them caught their breath and finished the sentence: "This program is perfect to show our students just exactly how NOT to do Rogerian* therapy. *I think Rogerian was the term used but it's been a while.

A little latter we were involved in the (D)ARPA Speech Understanding Research (SUR) Program and some of the group was there all hours of day and night. Spouses and significant others tended to visit particularly in the crazy night hours and kept getting in our way. We would amuse them by letting them use Eliza on the Q32 Time Sharing System. One day, the Q32 became unavailable in those off hours for a long period of time. We had a Raytheon 704 computer in the speech lab that I thought we could use to keep visitors happy some of the time. So one weekend I wrote an interpretive Lisp system for the 704 and debugged it the next Monday. The sole purpose of this Lisp was to support Eliza. Someone else adopted the Q32 version to run on the new 704 Lisp. So in less than a week, while doing our normal work, we had a new Lisp system running Eliza and keeping visitors happy while we did our research.

The 704 Eliza system, with quite a different script, was used to generate a conversation with a user about the status of a computer. The dialogue was very similar to one with a human playing the part of a voice recognition and response system where the lines are noisy. The human and Eliza dialogues were included/discussed in A. Newell, et al., "Speech Understanding Systems; Final Report of a Study Group," Published for Artificial Intelligence by North-Holland/ American Elsevier (1973). The content of that report was all generated in the late 1960s but not published immediately.

The web site,, has a little more information about the Raytheon 704 Lisp. The SUR program was partially funded and on-going by 1970.