Famous quote by John Archibald Wheeler

"No phenomenon is a real phenomenon until it is an observed phenomenon"

About this Quote

John Archibald Wheeler’s assertion, “No phenomenon is a real phenomenon until it is an observed phenomenon,” introduces a profound reflection on the role of observation in defining reality, especially within the context of quantum mechanics. In classical physics, reality exists independently of observation; the moon is there whether or not someone looks at it. By contrast, Wheeler’s statement encapsulates a view rooted in quantum theory: the very act of observation is integral to the manifestation of a physical event.

At quantum scales, particles can exist in a superposition of multiple states until measured. For example, in the well-known double-slit experiment, a photon behaves as a wave and passes through both slits simultaneously unless observed. The moment an observer tries to determine which slit the photon passes through, its behavior changes, it acts like a particle, and the interference pattern characteristic of waves disappears. This strange dependence on observation challenges classical ideas about the objective existence of phenomena.

Wheeler’s perspective suggests that the fabric of reality is participatory; observation is not a passive act but actively brings events into being. This view resonates with the Copenhagen interpretation of quantum mechanics, in which probabilities collapse into definite outcomes upon measurement. It underscores a subtle interplay between consciousness (or measurement) and the physical world, raising philosophical questions about the nature of existence.

Such ideas extend beyond the laboratory. They challenge notions of determinism and objectivity, blurring the lines between the observer and the observed. Reality, in this framework, is not fixed or absolute independent of interactions. Instead, it emerges as a consequence of observation and measurement. Wheeler’s insight provokes us to rethink the nature of existence, suggesting our engagement with the world is more fundamental than previously imagined, reality itself, at least at its smallest scales, requires an observer to crystallize from a realm of potential into concrete fact.

About the Author

USA Flag This quote is from John Archibald Wheeler between July 9, 1911 and April 13, 2008. He/she was a famous Physicist from USA. The author also have 8 other quotes.
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