In the context of the double-slit experiment, the act of observation or measurement by a human eye does not directly cause the wave function to collapse. The collapse of the wave function occurs when the particle interacts with its environment, which typically involves interactions with other particles or measurement devices.
In the case of the double-slit experiment, the particles (such as electrons or photons) pass through the slits and interact with a screen or detector behind the slits, where their positions or paths are measured. The measurement apparatus, not the human eye itself, plays a crucial role in the collapse of the wave function.
The human eye, as a sensory organ, detects photons that enter it and allows us to perceive light. However, the individual photons that make up the observed light do not typically interact directly with the retina in a way that would collapse their wave functions. Photons are usually absorbed by molecules within the retina, triggering a series of biochemical processes that eventually lead to the perception of light.
It's important to note that in quantum mechanics, the process of measurement and the role of observers can be complex. The act of observation can introduce disturbances or interactions that influence the behavior of quantum particles. However, for typical macroscopic objects like human eyes, their interaction with individual particles in the double-slit experiment is negligible, and the collapse of the wave function is primarily determined by the interaction between the particles and the measurement apparatus.