Beams of light behave like waves when aimed through slits. This in and of itself is not surprising. When single photons (light particles) or electrons are sent through the slits they arrive as particles but in the pattern of a wave. This defies logic as it seems each particle is going through both slits and then interfering with itself to produce the pattern.
Physicists then changed the experiment to observe each slit to see what the photon/electron particles were doing. The simple act of observation however changed the behavior of the particles. When experimentally observed, no wave like behavior occurred.
Neils Bohr (the father of the
atom) interpreted this paradox with his philosophy of complementarity.
Bohr's principle of complementarity claims
that objects of knowledge contain complementary properties. Knowledge of a
property depends upon the reference frame of the observer, and knowledge
of one property excludes the simultaneous knowledge of the other. Here are some quotes from Bohr who won the Nobel prize for physics in 1922:
"Two sorts of truth: profound truths recognized by the fact that the opposite is also profound truth, in contrast to trivialities where opposites are obviously absurd. The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth. "
"How wonderful that we have met with a paradox. Now we have some hope of making progress."
Werner Heisenberg who developed the uncertainty principle was also an advocate for complementarity. Here is a quote by Heisenberg:
"There is a fundamental error in separating the parts from the whole, the mistake of atomizing what should not be atomized. Unity and complementarity constitute reality."
The views of Bohr and Heisenberg came to be known as the Copenhagen Interpretation of quantum mechanics. This interpretation assumed the nature of reality was uncertain and probabilistic rather than causally deterministic. For Bohr, quantum mechanics was a complete description of reality despite it's fundamental uncertainty. There is a non-material wave of probability that precedes physical manifestation. Einstein could not accept this arguing that 'God does not play dice'. Quantum mechanics also implied an even stranger phenomenon known as 'quantum entanglement'.
In quantum entanglement pairs of fundamental particles can become interdependent even when separated at great distances. When one entangled particle is measured the state of it's pair is known simultaneously. Einstein refrered to this as 'spooky action at a distance', and felt that there must be some hidden variables that quantum mechanics had not been accounted for. Since the time of Bohr and Einstein however, quantum entanglement has proven to be a true phenomena, first by theory and more recently by experiment. For once Einstein appeared to be wrong, there could be no (local) hidden variables.
Quantum mechanics has since been extended to what is now known as the 'Standard Model of Fundamental Particles'. According to the standard model and quantum field theory each fundamental particle is really just a special case of an underlying field. Fields are not stuff, but relations spread out in space. This goes for all fundamental particles such as photons, electrons, quarks (which make up protons), and the recently discovered Higgs boson. This short video by Sean Carroll provides a concise description of how the universe is made of fields.
Currently the physics community is divided over the proper interpretation of quantum foundations. The Copenhagen interpretation may still be the most favored, but there are many theories that can explain the experimental results. The interpretations seem to break down into metaphysical preferences. In the link above Sean Carroll prefers a 'Many Wolrds' interpretation which suggests that infinite universes underly the quantum waves of probabilities. This is a deterministic theory that preserves causality and suggests infinte branches off each quantum state although we only experience one. Another nobel prize winner Richard Feynman, suggested a varient sometimes referred to as 'Many Paths' described in this quote by Physicist Freeman Dyson:
‘Thirty-one years ago [1949!], Dick Feynman told me about his "sum over histories" version of quantum mechanics. "The electron does anything it likes," he said. "It just goes in any direction at any speed, forward or backward in time, however it likes, and then you add up the amplitudes and it gives you the wave-function." I said to him, "You're crazy." But he wasn't.’
Feynman was also quoted however as stating that nobody really understands quantum mechanics. If Feynman was right than us non-physicists should feel free to help ourselves to our own preferred meta-physical interpretation so long as it agrees with the experimental results. Currently my preferred interpretation is Bohr's complementarity. This brings us back to the concept of duality and my motivation for composing the post.
In the west we have a long history of focusing on the separation between 'things' and characterizing them as distinct dualities. One example is Descartes dualism with regard to the separation of mind and body. Another example would be the separation of man (or woman) from nature. For example free will in western philosophy has historically been conceived as mans ability to transcend his natural environment. More recent trends in the west have been to focus on the foundational reality of material things perhaps at the expense of the non-material.
The elimination of the non-material has been very successful in physics to a point. Even at the quantum level we can make precise predictions of what will emerge physically if we know the initial experimental conditions (which is an important caveat). Physical descriptions alone however do not move us closer to understanding hard problems like value, meaning, purpose, and consciousness. In his book 'Incomplete Nature',the evolutionary biologist Terrence Deacon makes an intruiging argument that it will be necessary to understand the contribution of 'what is not realized' or what is 'absent' in order to even to begin to understand the emergence of life. In making this argument Deacon borrows in part from Taoist philosophy and chapter 11 of the Tao Te Ching which describes the utility of emptiness.
"Thirty spokes share the wheel's hub;
It is the center hole that makes it useful.
Shape clay into a vessel;
It is the space within that makes it useful.
Cut doors and windows for a room;
It is the holes which make it useful.
Therefore profit comes from what is there;
Usefulness from what is not there."
(translation by Gia-fu Feng and Jane English)
This is an example of the Taoist version of complementarity. No-thing is fundamentally intrinsic to and of itself. Instead it is from the complementary relationship of apparently distinct things or concepts that would seem to oppose each other that usefulness emerges. Deacon would say that in self-organizing systems the physical structure that keeps things from being realized is what has important and useful implications. For example, we have as system of blood vessels that constrains where our blood can flow. If the blood could go anywhere it would not efficiently get where it needs to go. The vessels also need an emptiness within for the blood to flow smoothly.
There are different ways of at looking at what is fundamental. The deterministically inclined physicist might say that fundamental particles encompass the stuff from which all the other sciences emerge. Quantum field theory however suggests to others (see Ladyman & Ross) that it is relations, as opposed to stuff, that are fundamental. This resonates with me as relations in the form of complementary oppostion seem to have a great reach in their usefulness across the sciences and the humanities.
Life emerged from non-life and is not separate from fundamental physics. Man emerged from the simple living organisms, and in some ways we manifest distinct qualities such as the potential for consciousness foresight. It was likely the evolution of stable relationships rooted in seeming opposites such as safety and exploration, competition and cooperation, self-interest and altruism that led to our distinct qualities. Ultimately however we are part of nature and cannot transcend our conflicts with the natural world by focusing only on what makes us distinct.
I believe this approach allows us to see the necessity of conflict. We cannot transcend conflict by denial of it's necessity. Instead perhaps we can see how conflict and opposition can serve the quest for unity.
Update:
Just to be clear, by recognizing the necessity of conflict I am not suggesting we promote it's celebration. Similarly the embracing of a degree of uncertainty does not give warrant to wallow in ignorance. On the contrary I think it is necessary to have the humility to recognize where our fundamental uncertainties lie so that we may stimulate our curiosities to increase our ways of knowing to reduce those uncertainties. This is an example of what I intended by allowing opposition to serve the quest for unity.
Here are some fascinating followup articles :
