Topics Discussed in Lex Fridman Podcast #293 – Lex Fridman & Donald Hoffman: Case against reality, Spacetime, Reductionism, Evolutionary game theory, Consciousness, Visualizing reality, Immanuel Kant, Ephemerality of life, Simulation theory, Difficult ideas, Love, Advice for young people, Meaning of life and much more.

Lex Fridman Podcast: Conversations about science, technology, history, philosophy and the nature of intelligence, consciousness, love, and power. Lex Fridman is an AI researcher at MIT and beyond.

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Donald Hoffman

Donald Hoffman is an American cognitive psychologist and popular science author. He is a professor in the Department of Cognitive Sciences at the University of California, Irvine, with joint appointments in the Department of Philosophy, the Department of Logic and Philosophy of Science, and the School of Computer Science. Hoffman studies consciousness, visual perception and evolutionary psychology using mathematical models and psychophysical experiments. His research subjects include facial attractiveness, the recognition of shape, the perception of motion and color, the evolution of perception, and the mind–body problem. He has co-authored two technical books; Observer Mechanics: A Formal Theory of Perception (1989) offers a theory of consciousness and its relationship to physics; Automotive Lighting and Human Vision (2005) applies vision science to vehicle lighting. His book Visual Intelligence: How We Create What We See (1998) presents the modern science of visual perception to a broad audience. His 2015 TED Talk, "Do we see reality as it is?" argues that our perceptions have evolved to hide reality from us. Find the books mentioned in Donald Hoffman's conversation with Lex Fridman below.

Books Mentioned in this Podcast with Lex Fridman & Donald Hoffman:

Book Title: The Case Against Reality – How Evolution Hid the Truth From Our Eyes

Author: Donald Hoffman

Book Title: Vision

Author: David Marr

Exploring the Conversation: Humans are Detached from Reality | Donald Hoffman and Lex Fridman

In a thought-provoking conversation between cognitive scientist Donald Hoffman and AI researcher Lex Fridman, the notion that what humans perceive as reality is completely detached from true reality takes the spotlight. Hoffman challenges our intuitive understanding that our senses accurately reflect the world around us. Instead, he posits that evolution has shaped our perceptions to guide adaptive behavior, effectively hiding the truth from us. This conversation delves into the implications of this idea, touching upon the work of physicists, the limitations of space-time, and the quest for a deeper understanding of reality.

The Perception-Reality Divide

According to Hoffman, the reality we experience through our senses is not a direct window into the true nature of reality. He argues that evolution’s purpose in shaping our perceptions is solely to guide adaptive behavior, not to unveil the truth. Our perceptions, therefore, are a real experience and an adaptive set of perceptions, but they do not necessarily correspond to the objective reality that exists independent of our senses. This challenges the commonly held belief that our perceptions provide an accurate representation of the external world.

Evolution as a User Interface

Hoffman draws an analogy between our perceptions and a user interface on a computer. Just as users interact with a user-friendly interface without needing to understand the underlying hardware and software, our perceptions serve as a simplified representation of reality that aids in survival and reproductive success. If we were aware of the complex truth behind our perceptions, it would be overwhelming and impractical for our daily lives. Evolution has therefore “”hidden”” the truth from us behind this user interface, allowing us to navigate the world more efficiently.

Space-Time and the Scientists' Perspective

Hoffman highlights how physicists are now challenging the fundamental nature of space-time, which has been central to scientific theories for centuries. Combining the principles of gravity and quantum field theory, physicists have concluded that space-time is not the ultimate reality. These theories suggest that space-time is a useful construct but does not provide a complete understanding of the underlying nature of the universe. Physicists are now exploring new mathematical structures that go beyond space-time to gain deeper insight into the symmetries present in the data.

The Road to Progress

As the conversation unfolds, Fridman and Hoffman discuss the potential for a deeper understanding of reality beyond space-time. They emphasize the need for any new theories to project back into space-time and align with the principles of evolution by natural selection. This constraints the search for a deeper understanding of reality, ensuring that any new frameworks must support and explain the phenomena observed in our current world.


The conversation between Donald Hoffman and Lex Fridman challenges our assumptions about the correspondence between our perceptions and reality. Hoffman’s argument that our perceptions merely guide adaptive behavior and hide the true, complex nature of reality raises intriguing questions. By delving into the work of physicists and the limitations of space-time, the conversation opens up a rich exploration of our understanding of the world. As scientists and thinkers continue to push the boundaries of knowledge, new insights and perspectives on the true nature of reality may emerge.”