The Double Slit Experiment stands as a pillar in the edifice of quantum mechanics, demonstrating the paradoxical nature of the microscopic world. It is an experiment that should make anyone reconsider their understanding of reality. In its simplest form, it shows us that particles—whether photons or electrons—can behave like both waves and particles. 

When no one observes their path, they exist as a superposition of possibilities, creating an interference pattern, which is characteristic of waves. However, the moment an observer measures the particle's path, the superposition collapses into a definite state, and the interference pattern vanishes. This startling shift from wave-like behavior to particle-like behavior under the influence of observation reveals a disturbing but profound truth: reality is not a passive backdrop, awaiting discovery. It is shaped and brought into existence by the act of observation itself.

As if the mystery weren't profound enough, the delayed choice version of the experiment, proposed by physicist John Wheeler, pushes the boundary of logic even further. It suggests that the decision to measure the particle's path—whether to treat it as a wave or a particle—can be made after the particle has already passed through the slits, yet this decision seemingly affects the behavior of the particle retroactively. 

Here, time itself seems to bend, as the present act of observation appears to influence past events. In this seemingly paradoxical reality, the notion of the observer is thrust into the spotlight. Not only does the observer shape the reality they observe, but the very fabric of existence itself seems to shift in response to the information extracted. But what does this tell us about the true nature of observation? Is it the observer themselves that matters, or is it the act of information extraction that collapses the wave function?

Direct and Indirect Observers: The True Nature of Observation

We are inclined to assume that the observer—often personified as a conscious entity—holds the key to collapsing the quantum wave function. But what if we are missing the point entirely? What if it is not the observer themselves but the information exchange that determines reality?

Consider the direct observer (DO) : the entity that directly interacts with the quantum system. The classic example is someone who directly measures the position or momentum of a particle in the double slit experiment. The moment the DO interacts with the system, the wave function collapses, and the particle assumes a definite state, behaving as either a wave or a particle. Theact of direct observation appears to be integral to the quantum reality we perceive.

However, what about the indirect observer (IO)? This observer does not engage with the system directly but might receive information about the system through an intermediary. Even though the IO is not directly interacting with the quantum system, their eventual access to this information seems to bring the same collapse of the wave function. The indirect observer suggests that it is not the observer themselves in a conscious sense but the availability of information that ultimately determines the state of the system.

This shift in perspective raises profound implications for our understanding of reality. The role of the observer may not lie in their mere existence or consciousness. Rather, it is the exchange of information that triggers the collapse of the quantum state. The observer’s consciousness might simply be a conduit through which information is accessed, recorded, and processed.
 

Information Extraction: The Key to Wave Function Collapse

The wave function in quantum mechanics is an abstract mathematical representation of all possible states of a system. However, it is not until the moment of measurement—or, more accurately, the moment of information extraction —that the wave function collapses into a single, defined state. The system's probabilistic nature gives way to a concrete outcome only when the observer engages with the system and extracts information.

To understand this fully, we must acknowledge a simple but profound truth: reality does not exist independently of observation. In quantum mechanics, the observer—whether direct or indirect— does not merely “record” the system's state. They bring it into existence. 

This is what the Copenhagen interpretation of quantum mechanics proposes: reality is not something that is merely “discovered.” It is something that is created through the act of measurement. The wave function exists in a state of potential until it is observed, at which point it collapses into one of the possible states.

In this framework, information extraction becomes the central act that determines the state of the system. The collapse of the wave function is not a mysterious, mystical event but a simple consequence of information being acquired. The system shifts from a state of superposition, where all possibilities coexist, into a singular reality when information about it is extracted.

But let us pause for a moment and reconsider: if information is so central to the collapse of the wave function, then can it be said that reality itself is constructed from the information we extract from it? Is reality, in fact, a relational phenomenon —one that exists only in relation to the observer and the information they access?

Information and Reality: Is the Observer the Architect of Reality? What is the relationship between information extraction and the reality we perceive? It is not just that the act of measuring or observing a quantum system influences its state—it is that the very structure of reality is dependent upon the interaction between the observer and the system. This implies that reality is not objective and independent ; rather, it is co-created by the observer and the information they extract from the quantum system.

This brings us to a provocative conclusion: the observer does not simply perceive reality; they construct it. In the same way that a painter brings a blank canvas to life through the strokes of their brush, the observer shapes reality through the act of information extraction. This is a radical departure from classical notions of a fixed, external reality. It suggests that reality is subjective , dependent not only on the observer’s perception but on the very information that they bring into the system.

Now, let us take this exploration one step further and link it to a concept from ancient Indian philosophy, which might offer us insights into the profound nature of information extraction and the collapse of the wave function.

Advaita Vedanta: The Nature of Perception and Reality

In Advaita Vedanta , one of the most profound schools of Hindu philosophy, the ultimate reality is referred to as Brahman —the infinite, unchanging, and indivisible essence of existence. According to Advaita Vedanta, the material world that we perceive through our senses is not the ultimate reality but rather a projection of the mind —a veil of illusion called Maya . Our senses, clouded by ignorance (Avidya) , trap us in a world of duality and separation, making us believe in the reality of the world around us.

This concept of Maya and Avidya shares striking similarities with the wave function in quantum mechanics. Just as the wave function describes a state of infinite potentialities until it is measured, the world, as perceived by the ignorant mind, is a realm of infinite possibilities. It is only through perception —or more precisely, information extraction —that the world takes on the fixed, finite form that we recognize.

In Advaita Vedanta, the Atman (individual soul) is ultimately identical to Brahman, but it is through ignorance (Avidya) that the individual perceives a fragmented and illusory world. The illusion of duality is akin to the probabilistic nature of the quantum world, where everything exists in a state of superposition until observed. When the observer perceives the world through the lens of their senses, they collapse this potentiality into the reality they experience—just as the wave function collapses into a definite state upon measurement.

Therefore, the illusion of duality in Advaita Vedanta mirrors the idea that our perception, shapedby the information we extract from the world, creates the reality we experience. The world does not exist in an objective sense; it is, in fact, constructed by our perceptions and the information we process.

The Convergence of Quantum Mechanics and Hindu Philosophy

The insights from quantum mechanics and Advaita Vedanta converge on a single, profound truth: reality is not objective but is deeply influenced by the interaction between the observer and the observed. Whether in the collapse of the wave function or the illusion of Maya , the act of perception or information extraction shapes the nature of reality itself. The world we experience is not a fixed, external reality but a fluid, relational phenomenon shaped by the information we access.

In quantum mechanics, the observer is not a passive entity but an active participant in the creation of reality. Similarly, in Advaita Vedanta, the individual self (Atman) plays an active role in shaping the world of experience through its perception and understanding. Both traditions—the scientific and the philosophical—suggest that reality is co-created through the exchange of information and the collapse of infinite possibilities into a single, observable state.

As we delve deeper into the implications of these ideas, we must ask ourselves: If the universe itself is an expression of consciousness and perception, what does it mean to truly know it? What if, in the end, the key to understanding the cosmos is not merely in observation but in the wisdom of self-realization —the recognition of the oneness of Atman and Brahman, or the realization of our intimate connection with the universe itself?