How we explain things depends on our beliefs and world view.
Science is the systematic study of the behavior of certain phenomena (that is, regularities, uniformities) in the physical universe. Scientific study is based on observation, experimentation, measurement, and the formulation of universal laws that describe these facts and phenomena in general terms and enable prediction.
The process of describing regularities (i.e. things that happen in a particular way) is incomplete and never exhaustive because regularities are not exact and deterministic. There is actually quite a lot of approximation and simplification involved in this process. If an exact equation is desired, then these scientific laws, which are useful for prediction, must be formulated in mathematical terms; this represents the whole business of science.
The huge popularity of science is due to its practical results, such as the previous technological examples stated previously. Science is about studying regularities in the material world and describing those regularities in order to make predictions and to make possible the technology that we use daily possible.
It is important to stress that describing and making use of science is not about explaining, but rather using it to make sense of something; here, description is not to be confused with explanation. Therefore, science is about describing, not explaining. The moment a scientist talks about the meaning behind a law or regularity in nature and our ability to benefit from it, he is no longer talking science and he is venturing into the realm of metaphysics and the philosophy of science. Just because someone is a great scientist, it does not mean that he has a deeper insight into the meaning of the laws of the physical world and universe.
What science seeks to explain
Science does not answer questions of meaning or questions of agency (like, who is doing what for what reason? What is responsible for a given regularity?) and we cannot criticize science for not dealing with these questions. They may be important questions but it’s not the responsibility of the field of science to answer these questions. For example, consider the Law of Gravity. We drop a pen and it falls. Why did it fall? Because of gravity.
We observe that, without exception, the pen always falls when we lift it and drop it. Then we call the conjunction between performing an action and its regularity the law of gravity. This means that the law of gravity is simply the name we have given to this regularity; however, it does not mean that the pen is falling because of gravity. Gravity is the name given to the process, not an explanation for it, but in our minds both the name and the explanation for the phenomenon have become one and the same.
The question arises: Is it logically justified to explain an experience through a causal law that is derived through the same experience?
In the beginning, when scientists started asking these questions, it was unclear what the difference was between description and explanation. For a long time science was thought to be a venture competing with religion in providing answers for life.
Regarding natural laws, 19th century American philosopher Charles Peirce stresses on the point that natural laws serve as a description of natural events, not as explanations of these very events: “no law of nature makes a stone fall, or a Leyden jar to discharge, or a steam engine to work.” 1
A law of nature left to its self would be quite analogous to a court without a sheriff. A court in that predicament might probably be able to induce some citizen to act as sheriff; but until it had so provided itself with an officer who, unlike itself, could not discourse authoritatively but who could put forth the strong arm, its law might be the perfection of human reason but would remain mere fireworks. Just so, let a law of nature – say the law of gravitation – remain a mere uniformity – a mere formula establishing a relation between terms – and what in the world would induce a stone, which is not a term nor a concept but just a plain thing, to act in conformity to that uniformity? 2
The law of gravity is just a formula, just a name. It cannot make a stone act in accordance to it.
It is important to note that the notion of law is closely related to issues of agency and also to the affinity of the human mind to perceive natural phenomena and the possibility of finding patterns in nature beyond science (i.e. how is it that we are so in tune to what is happening in the world that we can pick up all these regularities?). These issues announce the “greatness” of science. When it comes to the affinity of the human mind to realize recurrent patterns in the universe, Peirce says:
. . . the mind of man is strongly adapted to the comprehension of the world; at least, so far as this goes, that certain conceptions, highly important for such a comprehension, naturally arise in the mind; and, without such a tendency, the mind could never have had any development at all. 3
Therefore, there would be no science if one could not grasp the regularities.
In our scientific inquiry, it is reasonable for us to be searching out these regularities and hoping that they will remain stable, but we cannot assume that we have explained how or why such regularities or laws are in effect. It may also be reasonable to say that there are regularities and we hope that these regularities and so-called universal laws will come into effect in the future so that technology can be made from predictions. There can only be hope, and not certainty, because science is based on observation and there may be some instances where the same observation may not occur.Even though science is based on exactitude, there is still a measure of hope and faith involved.
A scientific law states a repeated observation about nature. How do we come to the conclusion that we have a scientific law? Several events occur, (not just to the researcher) that hold to certain regularities, according to a certain pattern, and a generalized statement is formed. The process of generalization from a limited number of observations to form a universal statement or law is called the process of induction, or looking at a certain number of events and saying that things are going to happen all the time. The assumption under the process of induction is that the more observations made about a particular phenomenon, the more it will reinforce the law.
There is only one way for such an assumption to be true, and it has nothing to do with the number of observations. We assume a relationship or connection between the object and what occurs, the cause and effect. The assumption is that there is a necessary connection between the cause and the effect. One must be able to explain this connection in a logical way, not as something that depends solely on observation but something that necessitates the event. If this is unable to be done, if it is only based on observations, then induction is a problem. In formulating a scientific law, generalizations made through the method of induction are problematic.
Because of induction, the basic application of our inductive reasoning is twofold: firstly we think we can describe what we have seen by the use of universal laws, and secondly, that we can use these established laws in predicting what we will see. There is, however, a problem with the mechanics of the inductive process. Are we justified in formulating these universal laws simply on the basis of a discrete number of past observations that have been made?
For example, based on the scientific observation of planetary motion, we could suggest that “the sun will rise every day.” However, just because the sun has risen in the past, it does not mean that it will continue to do so either tomorrow or the next day. So the induction based on the number of occurrences of a particular phenomenon is illogical. There is no guarantee that we will ever see the sun rise again. The sense of faith we have in the scientific laws of planetary motions is based on the supposition that some kind of necessity has caused the sun to rise in the past and will therefore continue to cause the sun to rise in the future. We assume that the connection between the cause and the effect are necessarily related. To use another common example, everyone in Europe thought the statement “All swans are white” was true because every swan that they had ever seen was white. However, when travelers came back from Australia and New Zealand, they reported having seen black swans, thus providing a real life example of how induction can falter. This observation negated the previous generalizations.This brings us to the issue of causality.
Causality is the relationship between an event (the cause) and a second event (the effect), where the second event is understood as a consequence of the first. In relation to one another, induction only has to work sometimes whereas causality always has to work. It has little to do with the number of occurrences; it has to work for each cause-effect relationship. The consequence of this model of the world is that empirical knowledge is connected to the causal relations between objects and events. According to this view, the logic of scientific discovery is inductive. In other words, it infers universal laws from particular statements.
The logic of induction proceeds as follows: First, it conjectures that induction is valid, and then concludes that causation is true. Whereas, from the point of view of logic, it is just the other way around; induction can be justified only by proving that causation is logically valid i.e., that the relation between cause and effect is necessary. Induction is therefore logically not a justified method to attain universality. As the Australian-British philosopher of science Sir Karl Popper observes, scientific induction is “logically inadmissible,” that scientific “theories are, therefore, never empirically verifiable.”4
Can we count on the laws of nature? It depends. We can have faith in them; we can hope that they will continue to hold in the future but there exists no logical certainty. But we cannot prove that they will remain true because we cannot observe something that will occur in the future (the dogma of the experiment).
The British philosopher Bertrand Russell calls the dogma of induction, the “biggest scandal of philosophy.” He provides the example of a farmer and his chicken. The chicken notices that the farmer comes every day to feed it. It predicts that the farmer would continue to bring food every day. According to the principle of induction, each feeding event added justification to its prediction. Then one day the farmer came and wrung the chicken's neck. Russell's point is that induction cannot justify any conclusions!
Critical problems with the method of induction have been in discussion long before the more recent debates, and are often connected with the concept of causality. The same issue was also at the center of a heated debate among Muslim philosophers and theologians as early as the 12th century. This critical problem with the method of induction was also pointed out earlier by the 18th century Scottish philosopher David Hume. Hume stated that when we observe two events to be causally related, say a seed (a) resulting in the growth of a shoot or tree (b), what we in fact observe is only a contingent conjunction of two events. That is, the causation that we think we perceive is not actually “out there in the world” for us to observe. When we see two events and judge them to be causally related, it is merely through a habit of the mind, something we project onto the world. A necessary causal link, as such, is not guaranteed. Hume writes:
Were any object presented to us, and were we required to pronounce concerning the effect, which will result from it, without consulting past observation; after what manner, I beseech you, must the mind proceed in this operation? It must invent or imagine some event, which it ascribes to the object as its effect; and it is plain that this invention must be entirely arbitrary. The mind can never possibly find the effect in the supposed cause, by the most accurate scrutiny and examination. For the effect is totally different from the cause, and consequently can never be discovered in it.5
This means that causal laws of nature are not true logically and there is no concrete evidence that these will continue to hold in the future. We simply cannot postulate universal laws that tell us the way the world irrefutably is and will always be unless we have some good reason to trust such generalizations. And even if we could trust such universal laws as “the sun will always rise,” it is not clear how many times we would need to see the sun rise in order to justify proposing this law. Scientific observation, although detailed and informative, has no claim to being the irrefutable truth of the matter.
Sir Karl Popper offered a potential solution to this problem by thinking about the way we do science in a new light. Popper turned science on its head by claiming that we are looking at science in the wrong way. Instead of looking to science to provide us with theories that are definitive and true, Popper said that we should be looking to science to provide us with theories that we have failed to prove false for a very long time. This approach to science is referred to as “Falsificationism.” Less of a solution and more of a shortcut, it is a tool which we are allowed to use in the game of science. He describes the Falsification approach by noting that for the scientific method to be rational, it must make claims to knowledge that is logically sound. That is, science is not about making grand universal laws, but about the examination of individual observations. According to the model of falsification, science is concerned with evaluating and refining. What we commonly think of as scientific claims to knowledge, are only hypotheses that we accept till they are proved wrong.
Fundamentally, Popper accepts that science can never provide us with complete 100% certainty, but he claims that this is not really a problem because it is not actually science’s job. The purpose of science is to provide us with a theory that is likely to be true based on the fact that we haven’t yet managed to prove it wrong. One unfortunate consequence of this, however, is that you can only ever be certain of the things that you have proved wrong. We know, for example, that the world definitely is not flat. The problem with this fact is that, although certain, it is not particularly useful to know that something is definitely false. For Popper, the best we can hope for is that a given claim is corroborated at one instance in time and if we presume otherwise, we are begging the question of the uniformity of nature: that what has always been, will (for apparently no good reason) continue to be.
To recapitulate, science does not deal with explanation; this is the realm of metaphysics. How we explain things depends on our beliefs and world view.
Dr. Yamina Mermer is a member of the Scriptural Reasoning Group based at the Faculty of Divinity, University of Cambridge, UK.
Dr. Eren Tatari is Assistant Professor of Political Science, Rollins College, Florida.
1. Online Past Masters text, The Collected Papers of Charles Sanders Peirce, (University of Virginia E-text Center), 1.323. (The online texts is drawn from The Collected Papers of Charles Sanders Peirce, Vols. I-VI ed. Charles Hartshorne and Paul Weiss (Cambridge, MA: Harvard University Press, 1931-1935), Vols. VII-VIII ed. Arthur W. Burks (same publisher, 1958).
2. Ibid., 5.48.
3. Ibid., 6. 417.
4. Popper, Karl. (1959). The Logic of Scientific Discovery. Hutchinson & Co. (Original work published in 1935).
5. Hume, David. (1772). An Enquiry Concerning Human Understanding. Hackett Publishing Co.