# The woo explained! Quantum physics simplified. consciousness, observation, free will

## Arvin Ash

Signup for your FREE trial to The Great Courses Plus here: Quantum physics simplified. Are Consciousness and Free Will linked to quantum mechanics? The double slit experiment explained. What is the difference between observation and measurement? Since Quantum Mechanics is the basis of all modern microelectronics it is extremely important for you to be able to separate quantum mechanics facts from fiction. There are misconceptions about quantum mechanics. I explain as simply as possible how quantum mechanics actually works. In 1801, British physicist Thomas Young performed a double slit experiment which showed that light was a wave, because it formed an interference pattern as a wave would. So for most of the 19th century light was considered a wave. However, in 1887, German Physicist Heinrich Hertz discovered the photoelectric effect. This is where light can knock off electrons from atoms. But this was not triggered by certain colors regardless of the intensity, but only by higher frequencies of light. This was not the way a classical wave was supposed to behave. This mystery was solved by Albert Einstein who proposed that light was not a wave, but came in packets of energy, photons. And the energy of these particles was proportional to its frequency of the wave. So Young and Einstein’s results seemed to be in conflict. Was light a wave or a particle? In 1909, G. I. Taylor performed a double slit experiment such that only one photon was emitted through the double slits at a time. He showed that individual photons look like particles, but a bunch of photons behave together like a wave. This experiment was later performed with electrons which also showed the same pattern. But people were perplexed as to what a wave of an electron actually means. In classical mechanics, Newton’s second law makes a mathematical prediction about the path a physical object will take, if you know its initial conditions. Something that showed a similar mathematical description of the wave of electrons was needed. In 1925, Austrian Physicist, Erwin Schrodinger, invented such an equation that revealed the shape of this wave function. Unlike Newton’s equation, it is not deterministic. It evolves over time. The Psi in the equation, which looks like a trident, is a wave function. In 1926, German physicist, Max Born, worked out that the psi function was related to probability. The most accepted interpretation of the wave function, called the Copenhagen interpretation, says that until a measurement is made, this equation tells us that the electron is in all the potential positions at once. So when the measurement takes place, that’s when we say that its wave function has collapsed, because only at that point can we ascertain where where electron is or what its properties are. And this collapse of the wave function is where the main confusion occurs in quantum mechanics. There is no equation that outlines exactly how this collapse occurs after measurement. This has been called the measurement problem of quantum mechanics. I’ve been careful to use the word measurement instead of “observation” – which many textbooks and physicists use interchangeably. But observation in quantum mechanics does not require eyes. It is simply a measurement. So what is a measurement? When an electron bounces off an atom, that’s a measurement. An observation in physics does not mean a conscious observer. Just about anything can be an observation. If an atom in superposition interacts bumps into another atom, that’s an observation. In the double slit experiment, when a single photon hits the screen, it collapses the probability wave of the photon. It shows up as a particle. That same photon is acting as a wave prior to hitting the screen, because it hasn’t been measured yet. The screen measures it. If enough photons are fired, you get a distribution exactly as predicted by the wave function. The measurement made was a purely physical measurement. It would not matter if anyone or any animal looked at the measurement. Overall what we can see is that the fundamental underpinnings of nature are probabilistic not deterministic. Does this justify free will? No. Just because free will implies that your decisions are not deterministic, and quantum mechanics implies that the properties of small particles are also not deterministic, the two are not related. There is no science linking the two. #quantumphysics And consciousness is not required to collapse of the wave function. The universe exists whether we are here to observe it or not. The Great Courses Plus is currently available to watch through a web browser to almost anyone in the world and optimized for the US, UK, and Australian markets. The Great Courses Plus is currently working to both optimize the product globally and accept credit card payments globally.