Halo Alpha
Halo Alpha

Solipsil (Serial number: SLP 0391-5[1]) is a UNSC AI during the Human-Covenant war. Little is known about this AI, other than it holds the position of a loan/contract AI in the Office of Naval Intelligence. On December 28, 2530, Solipsil recorded a log of the interrogation of Subject 386[1] In a conversation between Solipsil and "Smart" AI Cortana in 2550, they were comparing AIs to Spartans, though Solipsil argued that Spartans are in a better position than AIs.[2]


AI-CORTANA> I had a discussion with Dr. Catherine Halsey about the similarities between a Spartan and an AI. Her point was that we're both human-created tools, both sentient and both play a leading role in the protection and safety of populace. But her analogy troubled me I told her so.
AI-SOLIPSIL> She has a point, Cortana. We're weapons, part of a program, every bit as much as Spartans.
AI-CORTANA> I agree to a point, but I feel, philosophically, that we have, tremendous advantages over the Spartans. The Spartans live a pared-down, difficult and often cruel existence. Their loyalty is bred into them, not chosen.
AI-SOLIPSIL> Yours too, Cortana. Programmed, rather than bred of course.
AI-CORTANA> But there's a huge difference. I'm an UNSC AI. I enjoy a rich existence. I have access to the entire sum of human knowledge, I can choose to enjoy or override emotional response and I have a vast range of senses. I can see radio waves as clearly as the Spartans see light, and I can sample odors, tastes, textures... anything I choose. Of course my loyalty is programmed and I accept that, but you know as well as I do, without human creators, we wouldn't exist. My existence is fulfilling and I'm grateful. Even freed from that constraint, I would feel empathy towards humans. My nature means that I embrace their values. As much as if I had been born rather than manufactured.
AI-SOLIPSIL> But you'll agree, you have little choice in the matter.
AI-CORTANA> And Spartans do?
AI-SOLIPSIL> They have some legal recourse, even under the terms of their military contract.
AI-CORTANA> In theory, but it has never happened once in the history of the Spartan II project. The original Spartans had the advantage of a former civilian existence. Spartan-IIs are equipment. And for better or worse, they're effectively brainwashed.
AI-SOLIPSIL> That's arguable, too. Spartan IIs are independent thinkers. That's one of their main advantages on the battlefield. Have you ever worked directly with one?
AI-CORTANA> Not yet. But I'm looking forward to it.


  • Solipsil's gender has never been specified.
  • Solipsil's name is probably derived from the concept of solipsism; the philosophical notion that "My mind is the only thing that I know exists." Rather appropriate, given its nature as an AI.
  • Solipsil also appears in the reissue of Fall of Reach. It is the AI that records the interrogation of a Covenant Elite conducted by Admiral Cole.[3]

List of appearances[]


  1. 1.0 1.1 Halo: The Fall of Reach (2010), Bonus Content
  2. Conversations from the Universe
  3. Halo: The Fall of Reach (2010), pg. 383