In 1963 the philosopher of science, Karl Popper, summed up his views in the title of his book, “Conjectures and Refutations: The Growth of Scientific Knowledge.” Better still, he described what I believe to be the central theme, the soul of science early on in the book (pp. 29-30):
“What we should do, I suggest, is to give up the idea of ultimate sources of knowledge, and admit that all knowledge is human; that it is mixed with our errors, our prejudices, our dreams, and our hopes; that all we can do is to grope for truth even though it is beyond our reach. We may admit that our groping is often inspired, but we must be on guard against the belief, however deeply felt, that our inspiration carries any authority, divine or otherwise. If we thus admit that there is no authority beyond the reach of criticism to be found within the whole province of our knowledge, however far it may have penetrated into the unknown, then we can retain, without danger, the idea that truth is beyond human authority. And we must retain it. For without this idea there can be no objective standards of inquiry; no criticism of our conjectures; no groping for the unknown; no quest for knowledge.”
To paraphrase, truth is the goal that science must always have, but can never quite touch. We can figure out when we’re wrong with reasonable certainty, but we can never know if we have captured the truth. We must always settle for the ever-more-accurate description and the next best guess. An apparent weakness, an inability to “know the truth,” is strength in disguise and is what makes science (and accompanying technology) so fertile. Instead of “true” versus “false” we work with “false” versus “not demonstrably false” or “possibly true.” There can be good negative proof, but there is no absolute positive proof. Ever. This makes the framework of science asymmetrical and open-ended, always subject to further exploration. The world of the spiritual, of religion, relies on “truth” arising from faith, but does not require evidence. Scientists chase the “truth” of objective reality in the physical (non-spiritual) world, but can never quite catch it – the search is never-ending. These two views are not necessarily in conflict and are not mutually exclusive, but they are very different and not to be confused.
Science is often a deeply creative business, but it is also very restrictive. One primary rule is that clear evidence cannot be ignored. For instance, the evidence that evolution has, somehow, occurred is simply undeniable to a scientist. This assertion says nothing about religion one way or another (nor does it say anything about the causal forces underlying evolution or any particular theory, including Darwin’s). Science and religion have little overlap because science cannot address questions about deities or prophets. It’s possible that the creationists are correct in their assertion that what we see in the world results from divine intervention, that all of our dating methods and other sources of data are wrong. God slapped down the entire, massive body of evidence from which scientists infer evolution in a few thousand years? Well, maybe. There’s no way science can falsify such a possibility since gods and their divine interventions are not subject to empirical testing. But every bit of available evidence in the world of science repeatedly corroborates the existence and patterns of evolution.
Creation myths, all of them, are just that – imaginary, alternative realities lacking evidence. Myths attempt to account for the origins of what we see around us, but all are beyond empirical examination. They belong not to science or biology, but to the world of comparative religion or anthropology, where one can consider the stories of creation from one culture and compare them with others. Genesis, where God makes the first human from a lump of clay, is an interesting story. In the legends of the coastal tribes of the Pacific Northwest, Raven coaxes the first little humans out of their clamshell, and this is another interesting story. You can believe one over the other, but the choice is based on faith or upbringing, not on evidence. On the other hand, Darwin’s particular ideas are too often presented not as theory or conjecture, but as some sort of revealed, understood truth. This is a religious treatment of evolution, not a scientific one, and it has plagued biology for a very long time.
A keystone of science is that scientists are allowed only one “hard,” unshakable, valid assumption while they are practicing science (what they do in their off-hours is their own business, and many good scientists consider themselves quite religious). Scientists must assume the existence of some sort of objective reality, where the objects, forces and interactions of the universe would be present regardless of the observer. Yes, of course that could be wrong, too. We could all be having a collective hallucination. But if we don’t assume an objective reality, what possible reason would we have for wanting to describe and understand our surroundings when our observations are merely dreams? There would be no reason to do science, no inspiration, and no point to our passionate curiosity if we didn’t believe we were describing objects and events that exist beyond ourselves. It has been argued that the presence of the observer alters the observation, and even the thing or event being observed. This may be of concern at the scale of the very tiny, but as my friend and one of my editors, Ruth Deery puts it, “…it is not implied that the astronomer makes any difference in the behavior of Betelgeuse, or even in the rate and flow of a river or the acceleration of a falling body.” It is necessary that we make observations, look for patterns and correlations, offer explanations, draw conclusions, and then move on.
Given that some sort of objective reality exists, we try to organize our perceptions of the regularities that appear to be part of it. Where, given appropriate conditions, comparable events occur over and over again, we can begin to surmise they are the result of a “law.” Our understanding of these regularities or laws is pretty poor, but as we build, test and modify theories, the accuracy of our descriptions of nature grows. We describe laws, and base theories and hypotheses upon them. We compare our theories against evidence, modify the theories, and then take another look. Laws (regularities), theories (explanatory accounts) and hypotheses (guesses about the material world) are all made of “soft” assumptions – all are subject to further interpretation and change, but we can (and must) assume their validity (at least temporarily) in order to build on them. The only “hard” assumption that must be made is the existence of objective reality itself. We may understand little of trees, forests, gravity or sound waves, but we assume the tree produces waves and makes a noise when it falls, regardless of the presence of an observer to hear the sound. I don’t see that we have another choice. To think that events only occur when there happens to be an observer seems awfully arrogant. This does not mean that our interpretations of our observations are not “theory-laden,” where we see what we would like, or expect, to see. But the structure of science is intended to guard against this, albeit not always successfully, because all of us tend to lean toward our own favorite ideas. When we pursue it honestly, science serves us well.