Truth has been defined as that which is in accordance with fact or reality. Reality for every individual is a function of the interactions of neurons in their brain. Since I can’t know the product of interactions in your brain, I may have a different interpretation of reality than you do. But both our versions rely on “facts”, the things that stimulate impressions in our brains. It is just that different brains may interpret facts differently so to understand “truth”, we have to understand the nature of “facts”. 

Facts in Science

A scientific “fact” is something that is always true, everywhere in the universe. A few years ago, a student of mine became curious about established “facts” in ecology. We searched the literature and found lots of “hypotheses” but could not find one where a hypothesis was proven true always and everywhere. (Jordan and Miller 1996). We found one in physics that always has been valid when observations are restricted to time spans greater than one millionth of a second and to locations within our solar system. Under these conditions, there has never been any known observations of an exception to the first law of thermodynamics. It states that energy cannot be created or destroyed, only altered in form. Another law of physics is gravity, which is based on the fact that two bodies in the universe interact with each other. Other than those, there are few facts anywhere in science. Even the second “law” of thermodynamics is not a fact but a statistical statement. Boltzmann showed that because certain processes do not seem to occur – for example the spontaneous conversion of heat into mechanical energy – does not mean they are impossible, but extremely unlikely. In microscopic systems consisting of only a few molecules, the second law is violated regularly, but in macroscopic systems which consist of vast numbers of molecules, the probability that entropy will increase becomes virtual certainty.

A practical way to look at scientific “facts” is to consider them as hypotheses with a high probability of occurring. Much of science consists of testing a hypothesis that one group of objects (experimental group) is significantly different from objects in a control group. Objects can be people, animals, or non-living objects. The more individuals comprising each group, the higher the statistical confidence of the outcome. A good place to look for facts is in the “hard” sciences. Hard science is often considered to be more rigorous, that is, it can better ascertain “facts” than soft science. Newtonian physics is the most rigorous of the sciences simply because it has the good fortune to have a very good statistical base. Each physical object used in an experiment such as determining what metal is the best conductor of electricity consists of billions and billions of experimental objects (atoms) for each metal tested.

The sequence of scientific fields from hard to soft would be: Newtonian physics, Chemistry, Biology, Ecology, Economics, Social sciences (sociology, anthropology). In the field of chemistry, the statistics, while not as good as in Newtonian physics, still are good enough that many hypotheses are considered facts. Take for example the periodic table of elements, considered by most scientists to be confirmed. In reality, the periodic table is a probability table. In an ordinary mixture of hydrogen gas, 0.0156% of the atoms are deuterium and 10 ^-18 % are tritium. As a result, the atomic weight of a gas in a tube labeled hydrogen may be 1.00000, or it may be 1.00784. In the social sciences, small sample size is the problem. In contrast to Newtonian Physics, quantum physics considers interactions between only two atoms.  Predictions have been only as good as predictions of the outcomes of a coin toss.

Facts in Biology

A problem in biology is that of hierarchy. A “fact” at one hierarchical level of organization is a probability at a lower level. At the organismal level of biology, a species is a fact. Ways of defining species include karyotype, DNA sequence, sequence, morphology, behavior or ecological niche.  Between closely related species, these characteristics vary along a continuum.  A species is not a fact but merely a conglomeration of probabilities. If in my field studies of birds, I capture an individual that I don’t recognize, I can test its DNA and compare the result to a known data bank. Depending on the similarity of the best match, I can determine the probability that my catch belongs to a known species. At the level of DNA, the concept of species is based on probabilities. Functional processes such as photosynthesis that also are a fact at the organismal level of organization are probabilities at the biochemical level where myriad metabolic pathways comprising photosynthesis are subject to alteration by chance mutation, to random mistakes, or to interference by disease.

Institutional Facts

There is a distinction between scientific facts, and institutional or administrative facts that are simply a convention that enables humans to organize their existence.  Institutional facts are used routinely in court. I had beer with Andy Capp at the Rose and Crown the night of a crime is an institutional fact that can be verified by the bartender. His testimony indicates a high probability that I did not commit the crime. However, institutional facts are not always certain. The prosecution might bring a witness who testified he was at the Rose and Crown the night of the crime and never saw me, just someone who looked like me.

It is a fact that in 1930, my grandmother owned a house in Tilset, East Prussia (part of Germany). That fact could have been verified by looking at town’s property records.  However at the end of the second World War, East Prussia became part of Russia. My grandmother along with all other Germans were deported to refugee camps in Denmark, and her house was given to a Russian.  So it no longer is a fact that my grandmother owns that house. History has a way of changing institutional facts.

The first European explorer visiting Africa who labeled an animal with a long neck a “giraffe” did not make a scientific discovery.  He merely applied a label.  Labels are not scientific facts but simply administrative conventions. Many people believe it is a fact that the sky is blue. “Blue” is not really a fact but merely a word that we use to communicate the sensation we have when looking at the sky on a clear day.

 Is There Truth?

If there is doubt as to what constitutes a fact, how can we ascertain “Truth”?  Truth has been defined as that which is in accordance with fact or reality, but if institutional “facts” are nebulous, and scientific “facts” are merely probabilities, what does this say about “Truth”?   Except for thermodynamic laws, “Truth” is a probability. 

Literature Cited

Jordan CF, Miller C (1996) Scientific uncertainty as a constraint to environmental problem solving: large-scale ecosystems. In: Lemons J (ed) Scientific Uncertainty and Environmental Problem Solving. Blackwell Science. Cambridge Mass. p 91-117