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Reductionism is the “tendency to reduce certain notions, whether everyday ones, like physical objects, or theoretical ones in science, like electron, to allegedly simpler or more basic notions … To reduce a theory or a science to another is to show that the latter can in principle yield all the results of the former, e.g. that everything psychology tells us we could in principle learn from physiology.” (A Dictionary of Philosophy, A.R. Lacey).
It is a common dogma within philosophical circles to suppose that all the laws of the universe reduce to the laws of physics. Let us examine this notion by examining physics itself. Newtonian physics involves the analysis of the behavior of macroscopic objects: solids, liquids and gasses. In the cases of fluids, i.e. liquids and gasses, it is supposed that these are composed of molecules that are assumed to be objects with a discrete volume and weight; just like macroscopic solid objects except much smaller. “Solids” are themselves objects with length, breadth, height and weight that are composed of molecules whose characteristics are not usually relevant to the analysis of the behavior of the solid object. The behavior of the molecules themselves is analyzed using the laws of chemistry. Therefore, so far, chemistry would seem to be the most basic of the sciences. It was not until the early 20th century that atomic and nuclear physics began to be devised to investigate the behavior of and the nature of the atom and the atomic nucleus.
Nuclear physics describes the behavior of the large number of particles which compose the nucleus of the atom, many of which are as much “relationships between particles” as particles in their own right. The smallest nucleus is that of the hydrogen atom with just one “proton”, a particle with a positive electronic charge. The next element in the Periodic Table of the Elements is helium with two protons and two neutrons, particles with a neutral electronic charge. As we progress through the periodic table the nuclei become progressively larger and the particles “stack” upon each other in a very precise manner and according to precise and complex laws. However as we progress through the periodic table the defining feature of each element is that it has one proton more than the previous element and one less than the following element.
The nucleus is surrounded by an “electron cloud” composed of only electrons. The number of these negatively charged particles is always the same as the number of protons in the nucleus in order that the atom will have an overall neutral electronic charge. Now some atomic nuclei are more stable than others. This occurs when the number of particles in the nucleus, nucleons, reaches any one of a number of “magic numbers”. In a somewhat similar fashion the electron cloud surrounding the nucleus is physically stable when the number of electrons in the outer shell is eight; excepting hydrogen and helium where the “magic number” equivalent is two electrons.
Here we see that while the physics of the atomic electron cloud is, at least partly, an emergent property of the physics of the atomic nucleus it cannot be said that atomic physics is reducible to nuclear physics.
Much of chemistry entails the study of the interaction between atoms as they bond to form molecules. While an atom is electronically stable when the number of electrons is the same as the number of protons it is physically stable when, in most cases, there are eight electrons in the outer “shell”. Carbon is electronically stable with a total of six electrons thereby leaving the outer shell half full with four electrons. It will share four electrons with other suitable atoms in order to become physically stable. It may bond with, for example, four hydrogen atoms to become methane or with two oxygen atoms to become carbon dioxide.
The above observations point to the fallacy of the idea that all the laws of the universe reduce to either the laws of physics in general or to either atomic or nuclear physics in particular. The laws of nuclear physics describe the behavior of the large number of particles that exist in the nucleus. Atomic physics refer to the behavior of the electrons which orbit the nucleus. And chemistry describes how atoms interact to form molecules. Now the number of protons in a nucleus dictates the number of electrons required for electronic stability but the laws that describe the behavior of electrons in an electron cloud are different from and independent of the laws that describe the behavior of nuclear particles. Similarly the weight of an atomic nucleus and the number of electrons in the outer shell of an atom will create the parameters by which the atom in question will relate to other atoms, but the laws of chemistry are different from and independent of the laws of both the atom and the nucleus. Certain aspects of the nucleus will influence the two layers discussed here “above” the nucleus but reduction, per se, is a fallacy.
Similarly for the relationship between the physics of the atomic electron cloud and chemistry.
I am now sitting on a chair. To say “this chair is in this room” is true in an absolute sense. However to ask an electron, by way of a scientific experiment, the question: “where are you?” and demand an 100% accurate answer the response would have to be “somewhere in the universe”. In order to narrow this down to, say, an orbital near a particular nucleus would involve assigning a probability, such as 99%, that the electron is in that part of the universe.
The Copenhagen interpretation of quantum mechanics states that things do not so much exist rather they have tendencies towards existence that are only actualized by an interaction with an observer. It is not possible to assign a characteristic to something independently of that something being measured. The process of, say, narrowing down the whereabouts of an electron and assigning a probability figure regarding it’s position involves a macroscopic measurement device. Whenever a measurement of a small number of sub-atomic particles is made it inevitably involves a measurement device composed of billions of such particles. While the macroscopic measurement device and the microscopic measured entities are considered to be occupying different sorts of realities subject to different physical laws precisely at what number of particles the distinction occurs is not definable. In practical laboratory situations this poses no problem since the difference between the respective numbers involved is so enormous. And there is, also, a fundamental difference between the observing consciousness and the observed particles. The observing “mind” is a completely different sort of thing from the rest of “physical “ reality even if the relationship between the mind and the physical brain may entail a degree of mystery as to the nature of the processes involved in the emergence of the mind from the brain.
The sad tale of Schr dinger’s cat is well known. A cat is placed in a sound and light proof box. Pointing at the cat is a gun. The trigger of the gun is connected to a device set to either fire or not fire the gun according to a 50% probability. This may, for example, involve a beam of light that may be either horizontally or vertically polarized. The device is triggered causing the gun to either fire or not thereby either killing the cat or not. If the Copenhagen interpretation is correct the cat is neither dead nor alive, but in some sort of state of suspended animation, until the box is opened and the state of the cat’s health is actually observed. It is meaningless to talk of a situation actually existing until it has been measured. Now of course it is meaningful to speak of a beam of light as being in an indeterminate state of polarization or indeterminate as to whether it is composed of particles or waves [1] but to speak of a cat that is both dead and not-dead is a nonsense. The upshot of this thought experiment is another non-reducible layer to reality if the Copenhagen interpretation is correct.
In the 1950’s an alternative mathematical analysis of observed nuclear particle behavior to the one invented in Copenhagen in the 1930’s was discovered, the Many Worlds interpretation. This entails much simpler mathematics but it has it’s own absurd implications. When the random generator either fires or does not fire the gun the entire universe splits into two separate universes identical in all respects except that in one universe the cat is alive and in the other it is dead. And the universe duplicates every time an event of this type occurs, whether it is observed or not. The many worlds interpretation offers a mathematically elegant solution to the “measurement problem” but involves an astronomical number of parallel universes and this number increases all the time.
Most physicists opt for the Copenhagen interpretation being the correct one. However some would argue that is not really the case. The measurement, whatever this might be, occurs in “this” universe while the alternative possibility emerges in the “other” universe which is unknowable to us. In practice it may be that the Copenhagen interpretation only seems to be the case a minority of physicists argue.
While the Copenhagen scenario clearly contra-indicates reductionism, there are distinct layers to reality including a non material mind, the many worlds interpretation allows for the possibility, but not the certainty, of a materially and mechanistically understood universe. However I would argue that the notion that all the laws of the universe reduce to the laws of physics is, in fact, a vague prejudice that all reality is a material phenomenon and that matter is a much simpler sort of thing than it is. The vagueness involves the notion that sub-atomic particles are just like macroscopic entities with clearly defined volumes and weights only smaller. Perhaps everything is, in fact, ultimately a material phenomenon but the “material” itself has no easily defined basic nature.
Brendan Burke MA(Phil)
[1] Light is considered to have a dual nature. “Ask” light a wave question and it will behave as if it was a wave phenomenon. Ask it a particle question and it will respond as if it was composed of particles. Waves and particles are diametric opposites.
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