Revised 15 September 2021

When we attempt to solve or resolve problems, we need to base our actions on reliable information as to the verity and extent of each problem. Most people respect science and look to science to provide reliable information. But what is science? How can we tell valid science from pseudoscience? This Sub-section and following Sub-sections provide an overview of answers to these questions. 

Scientists sometimes use the same words as lay people. An example is the word “energy”. For scientists, this word has a far more precise meaning than that which is used colloquially (See Sub-section: Work & Heat)

The word “theory” is commonly understood by laypeople to mean unsupported speculation and with this meaning in mind, some laypeople dismiss or disparage theories of science. An hypothesis is a proposal intended to explain certain facts or observations and a scientific theory is a scientific hypothesis which has survived testing. Other disciplines also use the word “theory” with the same meaning as used by scientists. For example, “music theory” is not just mere speculation. Scientific theories which have been confirmed multiple times over a long period are referred to as ‘Laws". Nature’ or ‘Laws of Physics’. The use of the word ‘law’ by scientists is different in meaning from that used by the legal profession. Scientific laws describe the phenomena of how things are and do not dictate how things should be. 

For many people, scientists seem to use excessive jargon. There is a need for scientists to use words with precise meanings of concepts shared by the community of scientists. For reasons of economy, it is convenient to use a single word term with precise definition in place of a sentence or many sentences. Scientist do not generally report the results of their research in newspapers or magazines. If a newspaper or magazine summarises that research, then the reporter or journalist should have sufficient grounding in the discipline to translate the “jargon” for a lay audience. Some scientists can do this superbly. Many cannot. 

Science deals with facts based on hard evidence provided by experiments and analysis. The word “science” comes from the Latin word “scientia” which means knowledge. Valid science provides reliable knowledge as opposed to mere opinion. This raises an important question. Is certain knowledge possible? The answer is no. 

Any endeavour to establish absolute certain knowledge is fraught with difficulties. Current knowledge or scientific theories about the world can never be conclusively proven. However, tentative knowledge to a high degree of probability is possible, but that knowledge will not necessarily be the final version. The technology that has transformed the lives of humankind over the past 400 years is proof that sufficient and adequate scientific knowledge has been attained. Over the same 400 years, the tree of science has split into many different branches. It is now impossible for anyone to have an up-to-date, specialist knowledge of every branch of science. 

Science is defined by its methodology and not its contents because all knowledge based on science is provisional. Scientific theories are replaced over time by new theories which have greater explanatory value able to account for discrepancies or anomalies in previous theories. Isaac Newton (1643-1727) initially developed his theories of motion and gravity in the early 1660s and completed his masterpiece Mathematical Principles of Natural Philosophy in 1687 (Westfall, 1983). Newton's laws of motion and gravity were replaced by Albert Einstein’s theory of general relativity in 1916 (Pais, 1982). Newton's laws of motion and gravity are perfectly adequate for astronomers to predict with precision the location of planets moving at relatively slow speeds compared to the speed of light, but not for objects moving at high speeds approaching the speed of light. Newton’s Laws of motion and gravity cannot predict with precision or fully explain the precession of Mercury's elliptical orbit around the sun nor predict or explain the deflection of light from distant stars grazing the edge of the sun on its path towards Earth during a total solar eclipse by the moon. Einstein’s general theory of relativity is more complete and has greater explanatory value. Historically, most theories have proven to be wrong or inadequate over time and have needed adjustments to align with observations. The best of science cannot provide absolute infallible truths. Scientific theories are developed and replaced over time, and it is the methodology of science which leads to further developments and replacement.  

What distinguishes genuine science from pseudoscience is its willingness to allow evidence to confirm or challenge its theories. The great philosopher Aristotle (384-322 BCE) believed that men have more teeth than women. Both men and women develop 20 primary or baby teeth which raises the question of whether Aristotle ever asked Mrs Aristotle to open her mouth to confirm his claim. Assume that by the time they married, Mrs Aristotle had lost some teeth due to decay. If so, then Aristotle failed to make sufficient observations to back up his claim. This failure was perhaps intentional or unwitting. Nonetheless, although Aristotle was the first philosopher to set out the different branches of science and to develop a comprehensive system of logic, he did not practice the methodology of modern science. 

According to Karl Popper (1963), “the criterion of the scientific status of a theory is its falsifiability, or refutability, or testability”. Sigmund Freud’s Psychoanalytic Theories fails this criterion because his theories are presented in an unfalsifiable form. No experiment could ever disprove them. 

Refer to the Recommended Books Sub-section: Scientific Method for the sources of this Sub-section and further reading.