A Scientific Method
by Antonio Zamora and Elena M. Zamora
The scientific method is the foundation of modern science. It is a process for making observations, recording data, and analyzing data that can be duplicated by other scientists. In addition, the scientific method uses inductive reasoning and deductive reasoning to try to arrive at an objective truth. Inductive reasoning is the examination of specific instances to develop a general hypothesis or theory, whereas deductive reasoning is the use of a theory to explain specific results.
The subject of a scientific experiment has to be observable and reproducible. Observations may be made with the unaided eye, a microscope, a telescope, a voltmeter, or any other apparatus suitable for detecting the desired phenomenon. The invention of the telescope in 1608 made it possible for Galileo to discover the moons of Jupiter the following year. Other scientists confirmed Galileo's observations and the course of astronomy was changed. However, some observations that were not able to withstand tests of objectivity were the canals of Mars reported by astronomer Percival Lowell. Lowell claimed to be able to see a network of canals in Mars that he attributed to intelligent life in that planet. Bigger telescopes and satellite missions to Mars failed to confirm the existence of canals.
This was a case where the observations could not be independently verified or reproduced, and the hypothesis about intelligent life was unjustified by the observations. To Lowell's credit, he predicted the existence of the planet Pluto in 1905 based on perturbations in the orbits of Uranus and Neptune. This was a good example of deductive logic. The application of the theory of gravitation to the known planets predicted that they should be in a different position from where they were. If the law of gravitation was not wrong, then something else had to account for the variation. Pluto was discovered 25 years later.
The apparatus for making a scientific observation has to be based on well-known scientific principles. The telescope, for instance, is based on magnification of an image using light refraction through lenses. It can be proved that the image perceived through the telescope corresponds to that of the object being observed. In other words, you can trust observations made through telescopes.
This is in contrast to magic wands, divining rods, or other devices for which no basis in science can be found. A divining rod is a "Y" shaped branch of a tree, which is supposed to be able to help to identify places where there is underground water. The operator holds the divining rod by the top of the "Y", and the single end is supposed to dip when the operator passes over a section of land where there is water.
What is the force that makes the divining rod dip? How does the divining rod "sense" the water? A scientist would try to answer these questions by experiments. Place the divining rod in a scale, for example, and then put a bowl of water under the divining rod. Is there a change of weight that indicates force? In another experiment the scale with the divining rod may be placed over a place known to have underground water, and over another place known to be dry.
If these experiments show no force being exerted on the divining rod, we have to conclude that divining rods cannot be used as instruments for detecting water. We also have to conclude that any movement of the rod is accomplished by the hands of the person holding it, no matter how much the person denies it.
One form of the scientific method is to 1) make observations, 2) create a theory that explains the observations, 3) extrapolate or make predictions from the new theory, and 4) verify the predictions with more observations. If the predictions do not agree with the observations, generate a new theory and repeat the process. The scientific method requires that theories be testable.
If a theory cannot be tested, it cannot be a scientific theory. Step 2 involves inductive reasoning, as described above. This approach can be used to study gravitation, electricity, magnetism, optics, chemistry, etc. Sometimes more than one theory can be proposed to explain observable events. In such cases, different predictions made with each theory can be used to set up experiments that select one theory over another. In the 17th century there were competing theories about whether electromagnetic radiation, such as visible light, consisted of particles or waves.
At the beginning of the 20th century Max Planck postulated that energy can only be emitted or absorbed in small, discrete packets called quanta. This seemed to favor the particle theory, particularly after Einstein demonstrated that light behaves like a stream of particles in photoelectric cells. However, diffraction experiments with electrons, which were considered particles because they had a measurable weight, showed all the characteristics of waves. In 1926, Erwin Schrödinger developed an equation that described the wave properties of matter, and this became the foundation for the branch of physics called quantum mechanics.
How can waves behave like particles and particles behave like waves? Some scientific facts are very hard to comprehend. Yet, these are observable phenomena verified over and over again by many people all over the world. The behavior of the speed of light is another physical fact that is hard to understand. The speed of light in a vacuum is approximately 299,792 kilometers per second. The speed is reduced by about 3% in air and by 25% in water. A famous experiment conducted by Michelson and Morely at the end of the 19th century showed that the speed of light was the same perpendicular to the orbit of the earth and parallel to the orbit of the earth.
The orbital speed of the earth of 29 kilometers per second could not be detected in the measurement of the speed of light. Einstein's theory of relativity is based on the constancy of measurement of the speed of light for all observers. A train has its headlight on. The speed of the light emanating from the train is the same whether the train is moving toward you or not! It is hard to accept, but many experiments for over one hundred years have come to the same conclusion.
Science has some well-known limitations. Science works by studying problems in isolation. This is very effective at getting good, approximate solutions. Problems outside these artificial boundaries are generally not addressed. The consistent, formal systems of symbols and mathematics used in science cannot prove all statements, and furthermore, they cannot prove all TRUE statements.
Kurt Gödel showed this in 1931. The limitations of formal logical systems make it necessary for scientists to discard their old systems of thought and introduce new ones occasionally. Newton's gravitational model works fairly well for everyday physical descriptions, but it is not able to account for many important observations. For this reason, it has been replaced by Einstein's general theory of relativity for most celestial phenomena. Instead of talking about gravity, we now are supposed to talk about the curvature of the four-dimensional time-space continuum.
Scientific observations are also subject to physical limits that may prevent us from finding the ultimate truth. The Heisenberg Uncertainty Principle states that it is impossible to determine simultaneously the position and momentum of an elementary particle. So, if we know the location of a particle we cannot determine its velocity, and if we know its velocity we cannot determine its location. Jacob Bronowski wrote that nature is not a gigantic formalizable system because to formalize it we would have to make some assumptions that cut some of its parts from consideration, and having done that, we cannot have a system that embraces the whole of nature.
The application of the scientific method is limited to independently observable, measurable events that can be reproduced. The scientific method is also applicable to random events that have statistical distributions. In atomic chemistry, for example, it is impossible to predict when one specific atom will decay and emit radiation, but it is possible to devise theories and formulas to predict when half of the atoms of a large sample will decay. Irreproducible results cannot be studied by the scientific method.
There was one day when many car owners reported that the alarm systems of their cars were set off at about the same time without any apparent cause. Automotive engineers were not able to discover the reason because the problem could not be reproduced. They hypothesized that it could have been radio interference from a passing airplane, but they could not prove it one way or another. Mental conceptual experiences cannot be studied by the scientific method either.
At this time there is no instrumentation that enables someone to monitor what anybody else conceives in their mind, although it is possible to determine which part of the brain is active during any given task. It is not possible to define experiments to determine objectively which works of art are "great", or whether Picasso was better than Matisse. So-called miracles are also beyond the scientific method. A person has tumors and faces certain death, and then, the tumors start shrinking and the person becomes healthy. What brought about the remission? A change in diet? A change in mental attitude? It is impossible to go back in time to monitor all variables that could have caused the cure, and it would be unethical to plant new tumors into the person to try to reproduce the results for a more careful study.
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