Why Scientific Questions Cannot be Answered Completely

FROM THE LECTURE SERIES: Joy of Science

By Robert M. Hazen, Ph.D., George Mason University

One of the great frustrations of science is that most scientific questions cannot be answered completely. There are certain questions that may not be scientific at a given time, but they may become so in the future. There are at least four factors that prevent scientists from obtaining complete answers to many scientific questions.

Image of infinite space with nebulae and stars.
Certain factors prevent scientists from getting absolute answers for scientific questions. (Image: Outer Space/Shutterstock)

Some Questions Are Not Scientific at Present

One of the facets of scientific inquiry is that some questions are not scientific at present, but they may become so in the future.

In 1900, before Edwin Hubble’s discovery of the galaxies, questions about the origin of the universe were not in the realm of science. They were pure philosophical speculations because there was no observation one could make about the universe that would tell them anything about its origin. After Hubble discovered distant galaxies, it opened a whole new realm of questioning about the origin of the universe.

Today, the study of human consciousness is probably beyond science as well. Scientists don’t have a good operational definition of consciousness. They don’t know how to quantify or define it. They don’t know how to study consciousness as any physical entity. But that situation may change in the near future.

This is a transcript from the video series The Joy of Science. Watch it now on The Great Courses Plus.

Factors for Unanswered Scientific Questions

The first factor that prevents scientific questions from being answered is known as experimental error. All measurements, no matter how accurate or how carefully done, contain some error.

An example that can be considered is measuring the thermal expansion of a metal bar. If a piece of metal is heated up, a bar, for example, about three feet long, is going to get a little bit larger. Thermal expansion is an exact measurement of how much longer the bar gets with temperature, and thus one can measure thermal expansion.

One can measure the length of the bar and the temperature, but no matter how carefully one does those measurements or how well the thermometer is designed, there is always going to be some error in the measurement of temperature.

The Experimental Error

There is always room for improvement in scientific experiments, and so the scientific process is never-ending, and some questions can never be completely answered. That is because new techniques for making these measurements are constantly being invented, so scientists can always improve the precision and the accuracy with which they make their observations and measurements.

Today, there are bigger telescopes, faster electronics, and more sensitive analytical methods that regularly improve people’s ability to make measurements.

Learn more about the nature of energy.

The Uncertainty Principle

Image of color atoms and electrons.
The uncertainty principle deals in quantum mechanics and applies to the subatomic scale—the scale of atoms and electrons. (Image: ESB Professional/Shutterstock)

Another reason why scientific questions cannot be answered is called the uncertainty principle that applies to the subatomic scale.

At that scale, every measurement that one can conceive of making, alters the thing that is being measured. This is one of the most unsettling discoveries of quantum mechanics because it turns out at nature’s smallest scale—the scale of the electron and the atom.

Everything that one can use to measure atoms and electrons has comparable energy to the atoms and electrons one is trying to measure.

Scientific Questions and Chaos

Chaos is another problem that prevents people from obtaining complete answers to scientific questions. Many natural systems are chaotic, and thus inherently unpredictable.

People believe in an orderly universe and in natural laws in which a given set of initial conditions leads to a predictable outcome. However, these chaotic systems are such that the slightest change in initial conditions in a given environment can affect the systems and their behavior drastically.

One of the ways this is described metaphorically is called the “butterfly effect.” The idea is that a butterfly, flapping its wings in Asia can change the weather pattern over North America several months later.

So even if an entire physical system obeys all the physical laws, and codify all those laws, one can never measure the initial state of a system with such precision and accuracy that one can predict how it is going to become if the system is chaotic.

Learn more about magnetism and static electricity.

The Speed of Light

A more, rather prosaic limitation on what people can know is the speed of light.

Image of a spiral galaxy.
The speed of light tells us about places in the universe where we would never go and, thus, cannot know what is happening there. (Image: Aphelleon/Shutterstock)

To the best of one’s knowledge, the fastest any physical object can travel is just under about 186,000 miles per second. It means there are places in the universe where humans would never be able to go.

There are distant objects for which humans cannot possibly know what is happening to them at the present. People can only see them because they are as far away as they were in the past. It also means that humans can never travel backward in time, at least with present technologies and the present understanding of the physical universe.

In spite of these and other inherent limitations in the natural world, the methods of science absolutely, positively provide the most effective, the most powerful tool that we have for understanding and for modifying the physical world.

Common Questions about Factors Preventing Scientific Questions from Being Answered

Q: What is meant by an experimental error?

In case of an experimental error, all measurements, no matter how accurate or how carefully done, contain some error. The scientific process is never-ending and there is always room for improvement in scientific experiments.

Q: What is the uncertainty principle?

The uncertainty principle applies to the subatomic scale, where every measurement that one can conceive of making alters the thing that is being measured.

Q: How does the speed of light prevent scientific questions from being answered?

The fastest any physical object can travel is just under about 186,000 miles per second, which means there are places in the universe where humans would never be able to go. This would inadvertently prevent scientific questions from being answered.

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