Although quantum mechanics was invented to account for submicroscopic objects, such as photon and atoms, many experiments have established that quantum mechanics does indeed apply to the macro-world as well (Nairz, Arndt, and Zeilingerzaq 2002). The quantum mechanical universe is fundamentally different from our classical perception of the world. To reconcile the two, we must either question quantum physics or review our act of perception. Century-old experiments have proven the validity of quantum theory. In fact, quantum mechanics is by far the most precise and reliable science that humans have ever grasped. Therefore, in order to resolve the incompatibility, it is reasonable to turn to an assessment of perception itself. The majority of physicists consider perception intact and accurate. This assumption may be the root of the classical /quantum perception contradiction.
This article reviews the act of perception and examines its accuracy in revealing true nature of our conception of the world. The brain is our main tool for examining physical reality, so in order to determine the validity of our perceptions, it makes sense to begin with a study of our brain’s physiology, and in particular how the brain receives sensory stimuli and how the received data is processed and envisaged in (delivered to) our awareness. Then we attend to contradictions between classical and quantum mechanical interpretations of the world and try to resolve the paradox by combining the two topics.
We perceive the world with our senses. The five common senses are vision, hearing, touch, smell, and taste. Our sense organs are mostly stimulated by waves. Our eyes are sensitive to a certain band of electromagnetic waves called visible light. Our ears sense another wave band, called sound frequency. Our skin also receives stimuli as waves. Skin senses are mechanical in nature. These senses respond to pressure, bending, or other mechanical distortions of a receptor. These distortions are mainly received from vibrational frequencies. The skin’s Meissner’s corpuscles respond to low frequency, whereas Pacinian corpuscles are triggered by high frequency vibrations. For example, if we vibrate a tuning fork in close proximity to the skin without touching it, we still perceive a tactile sensation. The vibration theory, suggested by Luca Turin, posits that odor receptors also detect the frequency of vibrations of odor molecules. Any molecule under normal temperature has a vibrational frequency and atoms in the molecule have a periodic motion. In contrast with "lock and key" models based on shape theory, Luca Turin proposed that the odorant molecule must first fit in the receptor's binding site; then, because of vibrational energy mode compatibility, electrons can travel through the molecule via inelastic electron tunneling, triggering the signal transduction pathway. Some studies support olfactory vibration theory while others challenge its findings. Taste may follow a different mechanism, since salty and sour molecules open the ion channels for passage of sodium ions or close the potassium channels, thus triggering the depolarization of taste receptors. Bitter and savory molecules work by stimulating a G protein–coupled receptor.
Regardless, of the method of triggering, sensation are received by brain through action potential. Action potential consists of pulse-like waves of depolarization that travel along the polarized axons of neurons. The flow of currents within an axon can be described quantitatively by cable theory. In simple cable theory, the neuron is treated as an electrically passive, perfectly cylindrical transmission cable, which can be described by a partial differential equation.
If our sensory receptors receive mostly waves from the outside world, how do we perceive these waves as objects? How do we sketch our so-called objective reality out of these waves? Within this article I will argue that our consciousness does not just reflect what is out there, In contrast, brain is active in creating perceptions. Take vision, for example. The retinex (combination of retina and cortex) theory of vision posits that the brain’s cortex compares the data it receives and creates an appropriate visual perception. James W. Kalat, in Biological Psychology, writes, “Visual perception requires a kind of reasoning process, not just retinal stimulation” (Kalat 2003, 154).
To further the discussion, let us explore the nature of matter. Objects are known to have a dualistic wave-particle nature. In 1704, Newton described matter as solid, massy, hard, and impenetrable. In the late 1800s, James Clerk Maxwell claimed that light is the propagation of electromagnetic waves. His claims were experimentally verified by Heinrich Hertz in 1887. As a result, the idea of waves as the sole component of light rays became widely accepted at the time. However, wave theory couldn't explain the photoelectric effect, a phenomenon in which electrons are emitted from a metal after it is exposed to light with sufficient energy. To solve the problem, in 1905, Albert Einstein proposed the particular nature of light. He postulated the existence of quanta (or units) of light energy, called photons, that have particulate qualities. This light quantum is solitary and localized. He was awarded the Nobel Prize in Physics in 1921 for his photo-electric theory. However, wave character of light could not be denied, particularly in light of Thomas Young's double-slit experiment, which provided solid evidence for the wave nature of light. Therefore, it was decided that light must have a simultaneously dualistic nature—it is both wave and particle.
In 1924, Louis-Victor de Broglie postulated that not just light but all matter has a wave-like nature. De Broglie was awarded the Nobel Prize for Physics in 1929 for his hypothesis. Since then, the common belief among physicists has been that matter has a dualistic nature—it concurrently has the characteristics of waves and particles.
Wave characteristics are more apparent in electromagnetic radiation when it is measured over relatively large distances and time spans. On the other hand, particle characteristics are more evident when measuring matter in small time scales and positions. But how can matter exist in this bizarre dualistic state? According to our classical perception, matter has a specific mass and volume. Matter is also perceived as local and tangible. Waves, on the other hand, are spread out. Waves and their associated fields (e.g., electromagnetic fields) expand outward without any boundaries. They do not have a specific mass or a specific shape. They imply a sense of fluidity. However, in the majority of everyday experiences, we perceive only the solid characteristics of matter. We see a ball as a solid, localized, and tangible object that is subject to external forces. Why do we not sense a ball as a wave?
In quantum mechanics, the fading wave characteristic of matter is known as wave function collapse. In this phenomenon, the spread out and multi-state wave is reduced to a local and distinct particle. In 1932, John von Neumann suggested that the collapse of wave function occurs in the consciousness of human beings. In other words, he believed that “objectification” (the act of interpreting incoming data as an object) is an invention of the human mind. James W. Kalat (2003, 167–168) from North Carolina State University writes,
Most visual researchers believe that neurons in visual cortex 1 respond to spatial frequencies rather than to borders or edges. How do we translate a series of spatial frequencies into perception? From mathematical standpoint, sine waves spatial frequencies are easy to work with, In a branch of the mathematics called Fourier analysis. It can be demonstrated that a combination of sine waves can produce an unlimited variety of other more complicated patterns … Therefore a series of spatial frequency detectors some sensitive to horizontal pattern and others to vertical patterns, could represent anything anyone could see. Still we obviously do not perceive the word as an assembly of sine waves, and the emergence of object perception remains a puzzle. (Hughes, Nozawa, and Kitterle 1996) Indeed, the activities of visual cortex 1 and 2 are probably preliminary steps that organize visual material and send it to more specialized area that actually identifies objects (Lennie 1988).
Are particle portion just an invention of our brain? Below, I explore whether the modern understanding of brain anatomy and physiology can shed light on this puzzle. At this time this is just a highly speculative hypothesis. However, there is enough evidence to justify the speculation, and if it proves to be valid, it will have very important ramifications in solving the puzzles in hand namely the classical perception/quantum perception paradox. Below, I will provide recent evidence from neurophysiology to substantiate the main argument in this commentary.
 Thomas Young's double-slit experiment showed interference phenomena in which two beams of light that are coherent interfere to produce a pattern. See Wikipedia, “Interference (Wave Propagation).”
 Since 1996 Turin has been the leading proponent of the vibration theory of olfaction. The theory proposes that a molecule's smell character is due to its vibrational spectroscopy in the infrared range. The theory is opposed to the more widely accepted shape theory of olfaction, which proposes that the vibrational spectroscopic properties of molecules can be an important determinant of their associated smell. See Absolute Astronomy, “Luca Turin” (2010).