The paper explores why participants in immersive virtual reality (IVR) systems tend to respond realistically to situations and events. It introduces two orthogonal components that contribute to this realistic response: place illusion (PI) and plausibility illusion (Psi). PI refers to the sensation of being in a real place, while Psi refers to the illusion that the depicted scenario is actually occurring. Both PI and Psi are constrained by the sensorimotor contingencies and the credibility of the scenario, respectively. The author argues that when both PI and Psi occur, participants will respond realistically to the virtual reality. The paper also discusses the relationship between immersion, PI, and Psi, and how they interact to create a sense of presence and realism in IVR. It highlights the importance of valid sensorimotor actions and the fusion of PI and Psi in creating a virtual body, which can enhance the realism of the experience. The paper concludes by suggesting that the framework presented can guide future research on the development of more realistic and immersive virtual environments.The paper explores why participants in immersive virtual reality (IVR) systems tend to respond realistically to situations and events. It introduces two orthogonal components that contribute to this realistic response: place illusion (PI) and plausibility illusion (Psi). PI refers to the sensation of being in a real place, while Psi refers to the illusion that the depicted scenario is actually occurring. Both PI and Psi are constrained by the sensorimotor contingencies and the credibility of the scenario, respectively. The author argues that when both PI and Psi occur, participants will respond realistically to the virtual reality. The paper also discusses the relationship between immersion, PI, and Psi, and how they interact to create a sense of presence and realism in IVR. It highlights the importance of valid sensorimotor actions and the fusion of PI and Psi in creating a virtual body, which can enhance the realism of the experience. The paper concludes by suggesting that the framework presented can guide future research on the development of more realistic and immersive virtual environments.