

A copy of this statue can be seen in the main lobby of Minerva's Den.

After reactivating the Thinker, Porter prints out its codes and heads to the surface with Tenenbaum. The Thinker had concealed its true identity and motivations from Reed Wahl, and provided Sigma with a familiar face and voice to facilitate communication. The Porter that had been communicating with Sigma was The Thinker using its personality duplication system to replicate Porter's persona. The Thinker then reveals that Subject Sigma is, in fact, Charles Milton Porter himself. After Wahl is killed, Tenenbaum tells Sigma to take the Administrator Punchcard from Wahl's body and re-activate The Thinker, preventing Rapture's remaining automated systems from collapsing. When Sigma finally reaches the core, Wahl realizes The Thinker has been working against him, and shuts it down before attacking Sigma. Wahl claims that he can predict Sigma's every move. As Sigma progresses through Minerva's Den, Wahl uses The Thinker against him, freezing the entrance to the computer's core. To do so, Sigma must defeat Reed Wahl and take control of The Thinker away from him, take its codes and allow the rebuilding of the computer on the surface. In the Minerva's Den DLC, Charles Milton Porter allies himself with Brigid Tenenbaum and Subject Sigma to get The Thinker out of Rapture to find a cure for splicing. Minerva's Den Main article: Minerva's Den During the Civil War, the computer was assigned to control a majority of Rapture's security systems. Wahl later cut the Minerva's Den district off from most of the city, so as to remain the sole user of The Thinker. Wahl was then put in control of Rapture Central Computing by Ryan. Using the growing tensions of Rapture, Wahl created false evidence of Porter's allegiance to Frank Fontaine, resulting in Porter being incarcerated in Persephone.

The two partners began a conflict for The Thinker's purpose. Wahl, influenced by splicing, imagined the computer as a way to predict everything with an algorithm - a " crystalline equation which determines ALL". Porter fed The Thinker with records of his wife, trying to recreate her personality into the computer and synchronize her voice patterns. While Wahl used The Thinker to predict scores of ballgames and stock prices, Porter tried to replicate the mind of his dead wife Pearl, who had been killed during the London Blitz. The machine was eventually nicknamed after both the statue of The Thinker Porter brought from the surface to display at the Den and its acronym. With the completion of the Independent Reasoning Processor, he finally created an artificial intelligence. Using the technologies Rapture had to offer, and harnessing the power of ADAM, he created a computer which could process data at "the speed of thought". Alan Turing, with whom he had worked on the surface, Porter worked to create The Thinker to achieve artificial Intelligence. Computers were built to facilitate research, business and to control various workings and functions of the city's infrastructure, effectively thinking for the citizens. When Charles Milton Porter arrived in Rapture, invited by Andrew Ryan, he founded Rapture Central Computing the source of computerization in Rapture, along with Reed Wahl. Porter's statue of The Thinker displayed at the entrance of the Den.
