Reed Wahl worked with fellow computer scientist Charles Milton Porter
in creating the Rapture
Operational Data Interpreter Network, better known as The Thinker
. The Thinker was both the most advanced mainframe computer of its time and the machine that controlled the infrastructure of Rapture, however problems began to arise when Wahl and Porter tried to use the machine for differing purposes. Wahl used the machine to predict the stock market and the outcome of sports games, utilising it for profit, and disagreed with Porter's attempt to use the machine to simulate his dead wife, Pearl, believing that humanising the machine would ruin it.
Like almost all of Rapture's denizens Wahl seriously harmed his psychological state by using the gene-altering chemicals known as ADAM
, and developed a psychotic obsession over the idea that The Thinker would eventually develop a predictive equation which would allow it to predict any and all events in the whole world. Looking to push Porter out of the picture and take control of The Thinker for himself, Wahl had The Thinker manufacture a phoney tape of Porter pledging alliance to Frank Fontaine
, political enemy of Andrew Ryan
and sent it to Ryan. Porter was taken to the penal colony of Persephone, leaving Wahl to work on discovering his theoretical equation. However, Porter returned seven years later, as an alpha series Big Daddy
named Subject Sigma
, led by scientist Brigid Tenenbaum
and The Thinker. The two wished to overthrow Wahl and return to the surface with the design for The Thinker.
Wahl held off Sigma, utilising his minions, security robots and even the infrastructure of Rapture, all the while convinced that he was nearing the discovery of the predictive equation. Not long before Sigma reached The Thinker's core Wahl realised that he and Porter were the same person and in a final battle Wahl used his plasmids, his turrets and the last of his minions to try and kill Sigma. Sigma, however, overpowered him, killing him and taking his punch card so that he could access The Thinker, print out its code and escape Rapture with it.