What Does Quantum Mechanics Tell Us About Reality?

Quantum mechanics is one of the most successful scientific theories in history. Its mathematical formalism makes stunningly accurate predictions, and its principles are embedded in technologies ranging from lasers to semiconductors. And yet—despite its extraordinary practical power—the theory says remarkably little about what reality is.

Quantum mechanics tells us how to calculate probabilities of outcomes, but not why those probabilities arise. It describes how measurements correlate with observations, but remains silent on what, if anything, is “really happening” between observations. This silence has left a gaping metaphysical question: What is the reality behind the math?

Most physicists are content to work within the predictive framework, sidestepping deeper questions about meaning or ontology. As physicist David Mermin once quipped, the common attitude is “shut up and calculate.” But others—including many of the field’s pioneers—insist that physics cannot avoid metaphysical commitments. Some interpretations treat quantum mechanics as a challenge to classical realism; others attempt to preserve it. Many propose radically new ontologies.

What follows is a summary of ten influential interpretations of quantum reality, adapted and expanded from Nick Herbert’s Quantum Reality. Though often mutually incompatible, each interpretation is consistent with experimental evidence—and each offers a different answer to what kind of world we actually live in.

1. There Is No Deep Reality

This view, associated with Niels Bohr and the Copenhagen school, holds that quantum mechanics does not describe a reality independent of measurement. The wavefunction is not a picture of a physical world but a tool for predicting observations. At the quantum level, there is no underlying “real” world in the classical sense—only the outcomes of measurements. As Bohr put it, “There is no quantum world. There is only an abstract quantum physical description.” Quoted in Becker, What is Real?, p. 54.

This anti-realist stance is unsettling to many, including Albert Einstein, who rejected the idea that reality could be reduced to mere appearances. “I like to think the moon is there even when I am not looking at it,” he famously remarked.

2. Reality Is Created by Observation

A more radical offshoot of the Copenhagen view posits that the act of observation does not merely reveal a property—it brings it into being. Before a measurement, properties like position or momentum do not exist in any definite form. Only observation “collapses” the wavefunction into a determinate state.

This idea gained traction in popular science through writers like Fred Alan Wolf. Fred Alan Wolf, Taking the Quantum Leap (Harper & Row, 1981). But it was seriously entertained by major physicists including John Archibald Wheeler, who coined the term participatory universe. Wheeler in Law Without Law, in Quantum Theory and Measurement, eds. Wheeler & Zurek, 1983.

Other advocates include Wojciech Zurek and Henry Stapp, both of whom explored observer roles and consciousness in quantum events.

3. Reality Is an Undivided Wholeness

Physicist David Bohm proposed an alternative to the Copenhagen view that restores realism, but in a profoundly non-classical way. According to Bohm, the universe is an undivided whole. Herbert describes this vividly: Nick Herbert, Quantum Reality, p. 214.

“Quantum wholeness is a fundamentally new kind of togetherness, undiminished by spatial and temporal separation…”

4. Parallel Universes

Hugh Everett’s “many-worlds interpretation” sidesteps the problem of wavefunction collapse by asserting that all possible outcomes of quantum events actually occur—in separate, non-communicating branches of the universe. Every time a quantum decision point is reached, the universe splits into multiple versions, each realizing a different outcome.

Though seemingly extravagant, this interpretation avoids ambiguity in the formalism and preserves unbroken unitary evolution. Some physicists favor it precisely because, as Herbert puts it, “the math works out better.” Nick Herbert, Quantum Reality, p. 206.

5. Quantum Logic

Some thinkers argue that the bizarre outcomes of quantum experiments reveal not flaws in our instruments, but flaws in our classical logic. Just as non-Euclidean geometry was necessary to describe curved space in general relativity, a new form of logic—quantum logic—may be needed to describe quantum events.

Physicist David Finkelstein put it this way: Finkelstein quoted in Herbert, Quantum Reality, p. 235.

“Einstein threw out the classical concept of time; Bohr throws out the classical concept of truth… Our classical ideas of logic are simply wrong in a basic practical way.”

6. Neorealism

This position holds that the quantum world consists of objectively existing particles and waves, just like the macroscopic world we experience. Einstein, Schrödinger, Planck, and de Broglie all held neorealist views. As Einstein wrote: Albert Einstein, Autobiographical Notes, p. 81.

“I still believe in the possibility of a model of reality—that is, of a theory which represents things themselves and not merely the probability of their occurrence.”

7. Consciousness Creates Reality

This view builds on observer-dependent interpretations but goes a step further: not just observation, but consciousness is required to bring reality into being. John von Neumann first suggested that collapse cannot occur in measuring devices alone—it requires a conscious observer.

Eugene Wigner later echoed this idea: Eugene Wigner, “Remarks on the Mind–Body Question,” in Symmetries and Reflections, 1967.

“The content of consciousness is an ultimate reality.”

8. Only Phenomena Are Real

This view combines elements of the first two and reflects the position held, explicitly or implicitly, by many contemporary physicists. It asserts that phenomena—things we can observe—are real, but the underlying substrate is not.

9. Relational and Participatory Realities (QBism & RQM)

QBism

Developed by Christopher Fuchs, Rüdiger Schack, and others, QBism reinterprets the wavefunction not as a property of the external world but as an agent’s personal tool for navigating experience.

RQM

Proposed by Carlo Rovelli, RQM holds that physical properties only exist relative to other systems. There is no “God’s-eye view” of the universe—only webs of relation. Carlo Rovelli, “Relational Quantum Mechanics,” International Journal of Theoretical Physics, 1996.

10. The Pauli–Jung Conjecture

Though not an interpretation of quantum mechanics per se, the collaboration between physicist Wolfgang Pauli and psychologist Carl Jung offers a visionary extension of some observer-centered interpretations.

The Pauli–Jung Conjecture proposes that mind and matter are not separate substances but complementary aspects of a unified underlying reality. Marie-Louise von Franz, ed., Atom and Archetype: The Pauli/Jung Letters, 1932–1958.

Where Does That Leave Us?

As Nick Herbert observed, quantum theory presents physicists with a two-fold crisis: (1) There are too many realities. (2) They are all preposterous.

For much of the 20th century, questions about the meaning of quantum mechanics were marginalized in mainstream physics. As Adam Becker recounts in What is Real?, those who asked foundational questions were often sidelined or excluded. Adam Becker, What is Real? The Unfinished Quest for the Meaning of Quantum Physics (Basic Books, 2018).

Today, however, the foundations of physics is a vibrant and increasingly respected discipline. Once-dismissed figures like Hugh Everett, David Bohm, and John Bell have been reappraised as pioneers.

For The Project, this revival is not just a disciplinary correction—it is a profound opportunity. The re-legitimation of foundational inquiry allows for bridges between physics and philosophy, science and subjectivity, theory and meaning. If consciousness plays a constitutive role in the cosmos, then the boundary between knowing and being begins to dissolve.

This invites not just new physics, but a new vision of reality—one that honors the complexity of both experience and structure.