Science is a path to gaining knowledge about the natural world. The study of science also includes the body of knowledge that has been collected through scientific inquiry. Scientists conduct scientific investigations by asking testable questions that can be systematically observed and careful evidence collected. Then they use logical reasoning and some imagination to develop a testable idea, called a hypothesis, along with explanations to explain the idea — finally, scientists design and conduct experiments based on their hypotheses.
Science seeks to understand the fundamental laws and principles that cause natural patterns and govern natural processes. It is more than just a body of knowledge; science is a way of thinking that provides a means to evaluate and create new knowledge without bias. At its best, science uses objective evidence over subjective evidence to reach sound and logical conclusions.
Truth in science is a difficult concept, and this is because science is falsifiable, which means an initial explanation (hypothesis) is testable and able to be proven false. A scientific theory can never wholly be proven correct; it is only after exhaustive attempts to falsify competing for ideas and variations that the theory is assumed to be true. While it may seem like a weakness, the strength behind this is that all scientific ideas have stood up to scrutiny, which is not necessarily true for non-scientific ideas and procedures. It is the ability to prove current ideas wrong that is a driving force in science and has driven many scientific careers.
Early Scientific Thought
Western science began in ancient Greece, specifically Athens, and early democracies like Athens encouraged individuals to think more independently than in the past when kings ruled most civilizations. Foremost among these early philosophers/scientists was Aristotle, born in 384 B.C.E., who contributed to foundations of knowledge and science. Aristotle was a student of Plato and a tutor to Alexander the Great, who would conquer the Persian Empire as far as India, spreading Greek culture in the process. Aristotle used deductive reasoning, applying what he thought he knew to establish a new idea (if A, then B).
Deductive reasoning starts with generalized principles or established or assumed knowledge and extends them to new ideas or conclusions. If a deductive conclusion is derived from sound principles, then the conclusion has a high degree of certainty. This contrasts with inductive reasoning, which begins from new observations and attempts to discern the underlying principles that explain the observations. Inductive reasoning relies on evidence to infer a conclusion and does not have the perceived certainty of deductive reasoning. Both are important in science. Scientists take existing principles and laws and see if these explain observations. Also, they make new observations and seek to determine the principles and laws that underlie them. Both emphasize the two most important aspects of science: observations and inferences.
Greek culture was absorbed by the Romans. The Romans controlled people and resources in their Empire by building an infrastructure of roads, bridges, and aqueducts. Their road network helped spread Greek culture and knowledge throughout the Empire. The fall of the Roman Empire ushered in the Medieval period in Europe in which scientific progress in Europe was largely overlooked. During Europe’s Medieval period, science flourished in the Middle East between 800 and 1450 CE as the Islamic civilization developed. Empirical experimentation grew during this time and was a key component of the scientific revolution that started in 17th century Europe. Empiricism emphasizes the value of evidence gained from experimentation and observations of the senses. Because of the respect, others hold for Aristotle’s wisdom and knowledge, his logical approach was accepted for centuries and formed an essential basis for understanding nature. The Aristotelian approach came under criticism by 17th-century scholars of the Renaissance.
As science progressed, certain aspects of science that could not be experimented and sensed awaited the development of new technologies, such as atoms, molecules, and the deep-time of geology. The Renaissance, following the Medieval period between the fourteenth and seventeenth centuries, was a great awakening of artistic and scientific thought and expression in Europe.
The foundational example of the modern scientific approach is the understanding of the solar system. The Greek astronomer Claudius Ptolemy, in the second century, using an Aristotelian approach and mathematics, observed the Sun, Moon, and stars moving across the sky and deductively reasoned that Earth must be at the center of the universe with the celestial bodies circling Earth. Ptolemy even had mathematical, astronomical calculations that supported his argument. The view of the cosmos with Earth at its center is called the geocentric model.
In contrast, early Renaissance scholars used new instruments such as the telescope to enhance astronomical observations and developed new mathematics to explain those observations. These scholars proposed a radically new understanding of the cosmos, one in which Earth and the other planets orbited around the centrally located Sun. This is known as the heliocentric model, and astronomer Nicolaus Copernicus (1473-1543) was the first to offer a solid mathematical explanation for it around 1543.
The Scientific Method
Science and scientists are wary of situations that either discourage or avoid the process of falsifiability. If a statement or an explanation of a phenomenon cannot be tested or does not meet scientific standards, then it is not considered science, but instead is considered a pseudoscience. Falsifiability separates science from pseudoscience. Pseudoscience is a collection of ideas that may appear scientific but does not use the scientific method. An example of pseudoscience is astrology, which is a belief system that the movement of celestial bodies influences human behavior. This is not to be confused with astronomy, which is the scientific study of celestial bodies and the cosmos. There are many celestial observations associated with astrology, but astrology does not use the scientific method. Conclusions in astrology are not based on evidence and experiments, and its statements are not falsifiable.
Science is also a social process. Scientists share their ideas with peers at conferences for guidance and feedback. A scientist’s research paper and data are rigorously reviewed by many qualified peers before publication. Research results are not allowed to be published by a reputable journal or publishing house until other scientists who are experts in the field have determined that the methods are scientifically sound and the conclusions are reasonable. Science aims to “weed out” misinformation, invalid research results, and wild speculation. Thus, the scientific process is slow, cautious, and conservative. Scientists do not jump to conclusions, but wait until an overwhelming amount of evidence from many independent researchers points to the same conclusion before accepting a scientific concept.
Science is the realm of facts and observations, not moral judgments. Scientists might enjoy studying tornadoes, but their opinion that tornadoes are exciting is not essential to learning about them. Scientists increase our technological knowledge, but science does not determine how or if we use that knowledge. Scientists discovered to build an atomic bomb, but scientists did not decide whether or when to use it. Scientists have accumulated data on warming temperatures; their models have shown the likely causes of this warming. However, although scientists are primarily in agreement on the causes of global warming, they cannot force politicians or individuals to pass laws or change behaviors.
For science to work, scientists must make some assumptions. The rules of nature, whether simple or complex, are the same everywhere in the universe. Natural events, structures, and landforms have natural causes, and evidence from the natural world can be used to learn about those causes. The objects and events in nature can be better understood through careful, systematic study. Scientific ideas can change if we gather new data or learn more. An idea, even one that is accepted today, may need to be modified or be entirely replaced if new evidence contradicts previous scientific ideas. However, the body of scientific knowledge can grow and evolve because some theories become more accepted with repeated testing or old theories are modified or replaced with new knowledge.
Scientific research may be done to build knowledge or to solve problems and lead to scientific discoveries and technological advances. Pure research often aids in the development of applied research. Sometimes the results of pure research may be applied long after the pure research was completed. Sometimes something unexpected is discovered while scientists are conducting their research. Some ideas are not testable. For example, supernatural phenomena, such as stories of ghosts, werewolves, or vampires, cannot be tested. Scientists describe what they see, whether in nature or a laboratory.
The scientific method is a series of steps that help to investigate the answer those questions; scientists use data and evidence gathered from observations, experience, or experiments to answer their questions.
However, scientific inquiry rarely proceeds in the same sequence of steps outlined by the scientific method. For example, the order of the steps might change because more questions arise from the data that is collected. Still, to come to valid conclusions, logical, repeatable steps of the scientific method must be followed.
A scientist will first try to find answers to their questions by researching what may already be known about the topic. This information will allow the scientist to create a good experimental design. If this question has already been answered, the research may be enough, or it may lead to new questions. For example, a farmer researches no-till farming on the Internet, at the library, at the local farming supply store, and elsewhere. She learns about various farming methods, what types of fertilizers are best to use, and what the best crop spacing would be. From her research, she also learns that no-till farming can be a way to reduce carbon dioxide emissions into the atmosphere, which helps in the fight against global warming.
With the information collected from background research, the scientist creates a plausible explanation for their question, called a hypothesis. The hypothesis must directly answer the question at hand and must be testable. Having a hypothesis guides a scientist in designing experiments and interpreting data. Referring back to the farmer, they would hypothesize that no-till farming will decrease soil erosion on hills of similar steepness as compared to the traditional farming technique because there will be fewer disturbances to the soil.
To support or refute a hypothesis, the scientist must collect data. A great deal of logic and methodology goes into designing tests to collect data so the data can answer scientific questions. Experiment or observation usually collect data, and sometimes improvements in technology will allow new tests to address a hypothesis better.
Observation is used to collect data when it is not possible for practical or ethical reasons to perform experiments. Written descriptions of observations are qualitative data-based, and this data is used to answer critical questions. Scientists use many various types of instruments to make quantitative measurements, typically based on the scientific discipline. Electron microscopes can be used to explore tiny objects or telescopes to learn about the universe. Probes or drones make observations where it is too dangerous or too impractical for scientists to go.
Objective observation is without personal bias and is observed the same by all individuals. Humans, by their nature, do have a bias, so no observation is entirely free of bias; the goal is to be as free of bias as possible. A subjective observation is based on a person’s feelings and beliefs and is unique to that individual. Science uses quantitative over qualitative objective observations, whenever possible.
A quantitative observation can be measured and expressed with a number. Qualitative observations are not numeric but rather verbal descriptions. For example, saying a rock is red or heavy is qualitative. However, measuring the exact color of red, or measuring the density of the rock (which can be traced to the proportion of certain minerals in the rock) is quantitative. This is why quantitative measurements are much more useful to scientists. Calculations can be done on specific numbers, but cannot be done on qualitative values.
A good experiment must have one factor that can be manipulated or changed, called the independent variable. The rest of the factors must remain the same, called experimental controls. The outcome of the experiment, or what changes as a result of the experiment, is the dependent variable because the variable “depends” on the independent variable.
Return to the example of the farmer. She decides to experiment on two separate hills that have similar steepness and receives similar amounts of sunshine. On one hill, the farmer uses a traditional farming technique that includes plowing. On the other, she uses a no-till technique, spacing plants farther apart and using specialized equipment for planting. The plants on both hillsides receive identical amounts of water and fertilizer, and she measures plant growth on both hillsides. In this experiment:
- What is the independent variable?
- What are the experimental controls?
- What is the dependent variable?
The independent variable is the farming technique – either traditional or no-till – because that is what is being manipulated. For a fair comparison of the two farming techniques, the two hills must have the same slope and the same amount of fertilizer and water. These are the experimental controls. The amount of erosion is the dependent variable. It is what the farmer is measuring. During an experiment, scientists make many measurements. Data in the form of numbers is quantitative.
Data gathered from advanced equipment usually goes directly into a computer, or the scientist may put the data into a database. The data can then be statistically analyzed to determine specific relationships between different categories of data. Statistics can make sense of the variability in a data set.
In just about every human endeavor, errors are unavoidable. In a scientific experiment, this is called experimental error. Systematic errors may be inherent in the experimental setup so that the numbers are always skewed in one direction. For example, a scale may always measure one-half ounce high. The error will disappear if the scale is re-calibrated. Random errors may occur because a measurement is not precisely analyzed. For example, a stopwatch may be stopped too soon or too late. Data errors can be corrected by taking several measurements and averaging them. If a result is inconsistent with the results from other samples and many tests have conducted, it is likely that a mistake was made in that experiment, and the inconsistent data point can be thrown out.
Scientists study graphs, tables, diagrams, images, descriptions, and all other available data to draw conclusions from their experiments. Is there an answer to the question based on the results of the experiment? Was the hypothesis supported? Some experiments support a hypothesis entirely, and some do not. If a hypothesis is shown to be wrong, the experiment was not a failure because all experimental results contribute to knowledge. Experiments that do or do not support a hypothesis may lead to even more questions and more experiments.
Let’s return to the farmer again. After a year, the farmer finds that erosion on the traditionally farmed hill is 2.2 times greater than erosion on the no-till hill. She also discovers that the plants on the no-till plots are taller and have higher amounts of moisture in the soil. From this, she decides to convert to no-till farming for future crops. The farmer continues researching to see what other factors may help reduce erosion.
As scientists conduct experiments and make observations to test a hypothesis, over time they collect many data points. If a hypothesis explains all the data and none of the data contradicts the hypothesis, over time, the hypothesis becomes a theory. A scientific theory is supported by many observations and has no significant inconsistencies. A theory must continually be tested and revised by the scientific community. Once a theory has been developed, it can be used to predict behavior. A theory provides a model of reality that is simpler than the phenomenon itself. Even a theory can be overthrown if conflicting data is discovered. However, a longstanding theory that has lots of evidence to back it up is less likely to be overthrown than a newer theory.
Science does not prove anything beyond a shadow of a doubt. Scientists seek evidence that supports or refutes an idea. If there is no significant evidence to refute an idea and a lot of evidence to support it, the idea is accepted. The more lines of evidence that support an idea, the more likely it will stand the test of time. The value of a theory is when scientists can use it to offer reliable explanations and make accurate predictions.
Introductory science courses usually deal with accepted scientific theory, and credible ideas that oppose the standardly accepted theories are not included. This makes it easier for students to understand complex material. A student who further studies a discipline will encounter controversies later. However, at the introductory level, the established science is presented. This section on science denial discusses how some groups of people argue that some established scientific theories are wrong, not based on their scientific merit but rather on the ideology of the group.
When an organization or person denies or doubts the scientific consensus on an issue in a non-scientific way, it is referred to as science denial. The rationale is rarely based on objective scientific evidence but instead is based on subjective social, political, or economic reasons. Science denial is a rhetorical argument that has been applied selectively to issues that some organizations or people oppose. Three (past and current) issues that demonstrate this are: 1) the teaching of evolution in public schools, 2) early links between tobacco smoke and cancer, and 3) anthropogenic (human-caused) climate change. Of these, denial of climate change has a strong connection with geographic science. A climate denier denies explicitly or doubts the scientific conclusions of the community of scientists who specifically study climate.
Science denial generally uses three rhetorical but false arguments. The first argument tries to undermine science by claiming that the methods are flawed or that the science is unsettled. The idea that the science is unsettled creates doubt for a regular citizen. A sense of doubt delays action. Scientists typically avoid claiming universal truths and use language that conveys a sense of uncertainty because scientific ideas change as more evidence is uncovered. This avoidance of universal truths should not be confused with the uncertainty of scientific conclusions.
The second argument attacks the researchers who’re findings they disagree with. They claim that ideology and an economic agenda motivate scientific conclusions. They claim that the researchers want to “get more funding for their research” or “expand government regulation.” This is an ad hominem argument in which a person’s character is attacked instead of the merit of their argument.
The third argument is to demand equal media coverage for a “balanced” view in an attempt to validate the false controversy. This includes equal time in the educational curriculum. For example, the last rhetorical argument would demand that explanations for evolution or climate change be discussed along with alternative religious or anthropogenic ones, even when there is little scientific evidence supporting the alternatives. Conclusions based on the scientific method should not be confused with alternative conclusions based on ideologies. Two entirely different methods for concluding nature are involved and do not belong together in the same course.
The formation of new conclusions based on the scientific method is the only way to change scientific findings. We would not teach Flat Earth geology along with plate tectonics because Flat Earthers do not follow the scientific method. Using the fact that scientists avoid universal truths and change their ideas as more evidence is uncovered is how the scientific process works and shouldn’t be seen as meaning that the science is unsettled. Because of widespread scientific illiteracy, these arguments are used by those who wish to suppress science and misinform the general public.
In a classic case of science denial, the rhetorical arguments were used in the 1950s, ’60s, and ’70s by the tobacco industry and their scientists to deny the links between tobacco and cancer. Once it became clear that the tobacco industry could not show that smoking did not cause cancer, their next strategy was to create a sense of “doubt” on the science. They suggested that science was not yet fully understood, and the issue needed more study. Thus legislative action should be delayed. This false sense of “doubt” is the key component that misleads the public and prevents action. This is currently being employed by those who deny human involvement in climate change.