Philosophy of Science
From a historical perspective, the sub-discipline of philosophy of science is as old as Aristotle and, by the twentieth century, had risen to special prominence as a discourse.
To be sure, to the extent that the enterprise of science continued to record advancements in various aspects of human life, more and more philosophers made the enterprise of science their focus of study. Such focus found expressions in the area of philosophy of science—an area of discourse that could ordinarily be seen as a space of overlap between science and philosophy.
Yet, philosophers and scientists are not agreed upon as to the nature, character, and content of this space of discourse known as the philosophy of science. This rather odd situation found representation in the lamentation of Prince Louis de Broglie, the founder of the wave theory of matter, when he pointed out that "in the nineteenth century, there came a separation between scientists and philosophers...with scientists looking with some suspicion at the philosophical speculations that appear to them too frequently lacking in precision and attacking vain problems.".
The philosophers, on the other hand, were no longer interested in the special sciences as their results were considered rather narrow. This separation, for Broglie, has turned out to be harmful to both philosophy and science.
Perhaps an explanation for this apparent stand-off between scientists and philosophers in their representations of the nature, content, and character of the philosophy of science is that the central questions in the philosophy of science do not belong to science as such; the questions are about science but not part of science.
Of course, scientists can be philosophers of science, and sometimes they have been. The issue is that, when scholars are doing philosophy of science, they are not usually doing science per se, and most philosophers of science have not been practicing scientists. And so, the philosophy of science is not a branch of science; it belongs to the discipline of philosophy, intersecting with other areas of philosophy such as epistemology, metaphysics, and the philosophy of language.
The question, therefore, is: What is the philosophy of science?
In its very broad sense, the philosophy of science is the investigation of philosophical questions that arise from reflecting on science. The philosophical nature of these questions derives from their generality, fundamental character, and resistance to solutions by empirical disciplines such as history, sociology, and psychology. Furthermore, philosophical questions about science cannot be answered by scientists themselves, although being able to answer them often depends on having a good understanding of scientific theories.
Of course, science is important to philosophy as it seems to provide answers to fundamental philosophical questions. One such question is, "How can we have knowledge as opposed to mere belief or opinion?" This is the heart of epistemology, or the theory of knowledge. To this question, science has one general answer: "Follow the scientific method."
Thus, an area of philosophy that overlaps considerably with science is epistemology. And if we accept the idea that science actually does give us knowledge, then we must examine what scientific theories tell us about how the world is and decide what the scope of scientific knowledge is or what can be known about things that are. This is another area of overlap between philosophy and science. This is the area of metaphysics. Thus, the philosophy of science is both epistemology and metaphysics. And, since philosophy is related to science, let us at this point examine the nature and character of the discipline of science and scientific knowledge.
What is science?
The very enterprise, today referred to as science, is essentially the idea of the founders of the Royal Society of London, the oldest organization for the advancement of science in the world, chartered in 1662. Christopher Wren, Robert Boyle, and other founders were interested in the new 'philosophy' or natural science that was then emerging with the experiments and observations of men like Nicolaus Copernicus, Galileo Galilei, Sir William Gilbert, and Johannes Kepler.
Apart from this institutional or organizational conception of the enterprise of science, its semantic history presents the word'science' as derived from the Latin word'scientia,,' meaning 'knowledge', and the German word 'Wis ens chaff', which means'systematic, organized knowledge'. And so, science has been taken literally to mean 'knowledge'—the synthesis of the systematic study of every aspect of our experience of reality, especially objective reality, usually with the aim of reducing it to a logically consistent system of order.
By this understanding, science is identified with the domain of knowledge accumulated by a systematic study and organized by general covering principles; it is identified with knowledge covering general truths or the operation of general laws, a systematically acquired knowledge, testable or verifiable. Thus, in providing the storehouse of knowledge of the physical world, science is made up of an orderly system of facts that have been learned through study, observations, and experiments. Its form is an arrangement of concepts in their rational connections to exhibit them as an organic, progressive whole.
Furthermore, science is not only a body or a system; it is also a process—the process of gaining knowledge based on repeated observations in controlled conditions (experimentations) and attempting to explain what causes those observations through constructing hypotheses that can be tested experimentally. To this extent, science is the study of the natural world through observation, identification, description, experimental investigation, and theoretical explanations.
Science is therefore a way—a way of acquiring knowledge following certain universal methods—whose central feature is the testing of hypotheses and making predictions for the purpose of better understanding the universe.
According to Mervin Merken, science differs from the arts, religion, philosophy, and other fields in a very definitive sense. In his view, science is self-testing, self-correcting, and objective. Its practitioners, he says, publish their work and expose their data to the scrutiny of others who may repeat the experiments with essentially the same results or quite different results. Errors in interpretations are discussed openly. The final arbiter is experimentation or observation, not authority.
However, self-testing and self-correction in science do not necessarily result in universal agreement. It is impossible to achieve complete certainty and universal agreement in science since the discovery of a single fact may invalidate a theory. The most that can be said of scientific truth is that it has a high degree of probability. It is, however, important to state here that the very reason why science seems to differ from other forms of inquiry is its method.
To a very large extent, the enterprise of science has managed to present itself to the human mind as the most reliable cognitive scheme for addressing issues arising from the human condition. The scientific community claims that science is able to address most successfully the problems facing humanity because it is in possession of a special method by which it navigates the natural and social world, making observations of facts, drawing hypotheses, postulating theories, and discovering laws.
These facts, hypotheses, theories, and laws, along with assumptions and other claims of science, constitute what is referred to as scientific knowledge.
The Nature of Scientific Knowledge
What is generally referred to as scientific knowledge consists of claims about the world, statements about facts, observations of facts, hypotheses, theories, and laws. Scientific knowledge also includes the method(s) of arriving at such knowledge; in sum, it has to do with the body of assumptions, axioms, principles, and procedures of science. We now attempt to make some statements about these constituents of scientific knowledge.
1. Scientific Facts
Traditionally, a fact is the worldly correlate of a true proposition—a state of affairs whose obtaining makes a proposition true. Thus, facts are actual states of affairs possessing an internal structure of competence for objects, properties, or relations. What is so special about science is that it derives from facts rather than being based on personal opinion. Indeed, as J.J. Davies writes, "Science is a structure built upon facts.".
Knowledge based on the enterprise of science is derived from what we can see, hear, and touch, rather than from personal opinion or speculative imaginings. The assumption in this regard is that if observation of the world is carried out in a careful, unprejudiced way, using the senses, then the facts established in this way constitute secure, objective knowledge.
Three components of the nature of scientific facts assumed to be the basis for the formulation of scientific knowledge can be distinguished. They are that:
- Facts are directly given to careful, unprejudiced observation through the senses;
- Facts are prior to, and independent of, scientific knowledge; and
- Facts constitute a firm and reliable foundation for scientific knowledge.
In deriving laws and theories from facts, hypotheses are first constructed, which are then tested, and if several tests confirm the hypotheses, they become theories before they become laws. Indeed, once facts are obtained through observation, they are represented as statements, a class of which, in the scientific enterprise of deriving knowledge, constitutes hypotheses.
As such, facts are represented as hypothetical statements, which are meant to be employed as guides in the build-up of scientific knowledge, especially at the experimental stage. It is, however, pertinent to state here that, in relation to the formulation of hypotheses and the construction of theories, observation is central to the formation of knowledge in science. Indeed, observation and experimentation are central to the process by which knowledge is acquired in science.
2. Hypothesis
A hypothesis is some kind of hunch, a speculation proposed as a possible solution to a problem. A hypothesis usually requires further investigation of its acceptability by argument, observation, or experiment. Hypotheses are indispensable to human thinking. They are used by everyone, from detectives to metaphysicians.
They form the basis of an influential account of the scientific method, the hypothetico-deductive method, closely related to the claim, associated with Popper, that scientific theories are empirical hypotheses and remain so, however successful they are at withstanding respected attempts to falsify them.
The formulation of hypothesis constructs or tentative explanations, which almost always consist of a system of several conceptual statements designed to provide predictions and explanations, involves the method of scientific reasoning known as abduction. In this light, a hypothesis in science can be described as the initial construct of scientific knowledge needing confirmation through testing.
In science, hypotheses have sometimes been referred to as "educated guesses," which are based on prior knowledge and observation regarding the cause of a particular phenomenon. Seen as such, it is taken to be a tentative solution or explanation for an unexplained occurrence that does not fit into the existing structure(s) of knowledge.
In relation to scientific theory, a hypothesis is the statement of an idea that can become a theory, which is the next step, after experimentation(s), in the scientific method. It is to be noted that the basic idea of the statement of a hypothesis is that there is no predetermined outcome as to the proposed explanation contained in the hypothesis. And so, for a hypothesis to be termed scientific, it has to be something that can be supported or refuted through carefully crafted experimentation.
The primary trait of a hypothesis, then, is that what it proposes can be tested and that such tests can be replicated. Indeed, a hypothesis, which is often in the form of an "if/then" statement, is often examined by multiple scientists to ensure the integrity and veracity of the experiment. Upon analysis of the results, a hypothesis can be rejected or modified, but it can never be proven to be completely and entirely correct.
For example, relativity has been tested so many times that it is now generally accepted as true, but there could be an instance that has not been encountered where it is not true. However, as sufficient data and evidence are gathered to support a hypothesis, it becomes a working hypothesis, which is a milestone on the way to becoming a theory.
Only after hypotheses have been confirmed, at least on the basis of available information, do they assume the status of scientific theories. As such, when enough evidence accumulates to support a hypothesis, it moves to the next step, known as a theory, in the scientific method and becomes accepted as a valid explanation of a phenomenon. Indeed, a scientific theory summarizes a hypothesis or group of hypotheses that have been supported with repeated testing (experimentation).
3. Theory
Scientific theories are the carriers of scientific knowledge. It is the attempt to bind together in a systematic fashion the knowledge that one has of some particular aspect of the world of experience. The aim is to achieve some form of understanding, which is usually represented in the forms of explanatory power and predictive fertility.
As used in science, a theory is an explanation or model based on observation, experimentation, and reasoning, especially one that has been tested and confirmed as a general principle that helps to explain and predict natural phenomena.
Scientific theories represent an important discourse in understanding scientific knowledge. To be sure, if any issue can be justifiably deemed central to the philosophy of science and its concern with knowledge, it is that of the nature and structure of scientific theories, together with the diverse roles theories play in our understanding of the nature of scientific knowledge; for theories are the vehicle of scientific knowledge, and one way or another, they become involved in most aspects of the scientific enterprise.
The traditional analysis, going back to the Greeks and most recently championed by such logical empiricists as Carl Hempel and Ernest Nagel, sees theories as 'hypothetico-deductive systems', meaning that one has a set of laws bound together through the fact that, from a few high-powered axioms or hypotheses, everything else can be shown to follow as deductive consequences.
Explanation, therefore, is a matter of showing how things happened because of the law of the theory. Prediction is a matter of showing how things will happen in accordance with the laws of the theory. Most significant is the fact that really successful theories bind information from many hitherto disparate areas of experience, thus exhibiting what the philosopher William Whewell characterized as a 'consilience of inductions.'
Besides the use of the term to name a whole area of inquiry, in science, "theory" is also employed to indicate a body of explanatory hypotheses for which there is strong empirical support. Indeed, what is distinctive about a theory as it is used in science is that it goes beyond the explanations of particular phenomena to explain these explanations. That is, when particular phenomena are explained by an empirical generalization, a theory will go on to explain why the generalization obtains, as well as explaining the exceptions to the generalizations and the conditions under which it fails to obtain.
Theories, in short, unify, and they do so almost always by going beyond, beneath, and behind the phenomena that empirical regularities report to identify underlying processes that account for the phenomena observed. Given the role that scientific theories play in the formation of scientific knowledge, it is, however, important to note that scientific theories are not to be considered the end result of the scientific method.
This is because theories can be proven or rejected, just like hypotheses. They can also be improved or modified as more information becomes available, so that the accuracy of the predictive power of the theory becomes greater over time. Be that as it may, theories remain the foundations for furthering scientific knowledge and for putting the information gathered, at least at the early stage of the development of scientific knowledge, to practical use.
Though a further stage in the scientific method sees some theories becoming laws, theories and laws have separate and distinct roles in the scientific method. Whereas a theory is an explanation of an observed phenomenon, a law is a description of an observed phenomenon.
4. Laws
In science, a law is a descriptive principle of nature that holds in all circumstances covered by the wording of the law. There are no loopholes in the laws of nature, and any exceptional event that did not comply with the law would require the existing law to be discarded or would have to be described as a miracle. Eponymous laws are named after their discoverers (e.g., Boyle's law); some laws, however, are known by their subject matter (e.g., the law of conservation of mass), while other laws use both the name of the discoverer and the subject matter to describe them (e.g., Newton's law of gravitation).
A description of nature that encompasses more than one law but has not achieved the incontrovertible status of a law is sometimes called a theory. Theories are often both eponymous and descriptive of the subject matter (e.g., Einstein's theory of relativity and Darwin's theory of evolution). In relation to laws and theories, a hypothesis is a theory or law that retains the suggestion that it may not be universally true. Clearly, there is a degree of overlap between the three concepts of laws, theories, and hypotheses.
From the foregoing, scientific knowledge can be taken to be characteristically public in nature. Significant to this understanding is that scientists from different intellectual and cultural backgrounds can come to very close agreement in their enterprise. The idea that scientific knowledge is public knowledge is premised on the understanding that scientific theories are the vehicles for propagating scientific findings. And it is on this ground that a scientific theory is accepted.
That is, scientific theories are accepted only when they make useful and dependable predictions about the natural world that can be independently confirmed empirically. As such, scientific knowledge, it is claimed, is based upon naturalistic explanations and is thus empirically verifiable. In this understanding of scientific knowledge, theories play the all-important role of being the carriers of scientific knowledge, as they unify data and account for hitherto unexplained data, sometimes pointing to relationships that previously went unnoticed.
Scientific Methods
One of the characteristics of the popular image of science is that it is able to present itself as the paradigm of rationality because of the fact that it is in possession of a particular method. This is generally referred to as the scientific method. And so, we may ask: what makes a discourse scientific, and what makes its method peculiar? What distinguishes science from other things people do or study? It is not about the sorts or types of things science studies; it is about how it studies things. Usually, this has to do with describing a process or the standards required of a process, not any kind of object or category of things.
To be sure, the basic ingredients of scientific methods are a mix of observation, evidence, testing, and logic. As an example, your cereal in the bowl has something about the milk that does not seem right. You suspect the milk is spoiled. This is a hypothesis. So, you check the date on the carton, and you smell the content, and sure enough, the milk is old and sour. This is not just evidence in support of the spoilt milk hypothesis; it is corroborating evidence from two independent sources, the date and the smell. And the evidence itself is interpreted with the help of some background knowledge about the longevity of milk and the link between the sensation (the smell) and the situation (the spoilage). All of these methods happen over and over throughout the day as we come to terms with our environment.
To this extent, in our daily lives as well as in science, where there is neither supporting evidence nor logic-mathematical proof, there is no knowledge. And where there is inconsistency in the evidence or inconsistency in the evidence and theory, the responsible thing to do is withhold judgment either way. If the milk smells fine, for example, but the date is a month or more old, common sense suggests an attitude of "I cannot say whether the milk is spoiled or not." Anything more decisive would be baseless speculation. These are the standards we live by when we are being honest and responsible, and these are the standards at the heart of the scientific method.
However, the main difference between science and daily life experience is that the scientific process is more deliberate and explicit in following the steps and standards of the method. Science is also distinguished by a greater dedication to the result of the method than its characteristics in daily life. And so, science is more deliberate and dedicated than non-science in following the method. It is also more public and open to independent review. All of these features of science—the slow, deliberate, explicit, public application of reasoning from evidence—make the process clear and plainly visible.
Scientific Explanation
A major characteristic of the image of science is that science, as an enterprise, aims at the provision of explanations for events in the natural world. To this end, it is necessary to state at this point that the fountainhead of scientific explanation is provided by the deductive-nomological model. This we found represented in the 1948 Hempel-Oppenheim paper, which makes no pretense of explicating anything other than the deductive neologism of explanation.
The question that comes to mind at this point is: What is an explanation? In ordinary usage, an explanation is simply an answer to a 'why' question. Asking questions about why things are the way they are and offering explanations is part and parcel of human nature. We explain how others behave by making assumptions about their character, inferring causes that would explain why the event or phenomenon happened, and giving historical explanations of, for instance, wars and conflicts. When we already know or assume something to be true in a way that makes the explanation seem inevitable or predictable, we typically enjoy a sense of greater understanding.
Around the middle of the twentieth century, philosophical theories of scientific explanation coalesced around the project of accounting for explanation in logically grounded, non-psychological terms. This project was explained most clearly by the German-American philosopher Carl Gustav Hempel (1905–1997) in a series of papers. Hempel's model of scientific explanation is known variously as the 'Covering-Law Model', 'Deductive-Nomological Model', or simply 'D-N model'.
The basic idea of Hempel's model is that explanation typically takes the logical form of argument from premises that do the explanatory work (that is, from the explanation to the conclusion that follows from the premises). Not just any set of premises and conclusions, and much of the philosophical literature concerning the covering law model is to characterize which conditions the premises and conclusions must satisfy and what relations must hold between them.
Hempels sets out three main conditions. First, the premises are true, and so is the conclusion. The connection between the explanations and the explanadum is thus characterized by deductive logic. Secondly, the premises must contain at least one statement of a general law of nature, where this nomological (law-like) statement does some work in establishing the link between the explanation and the explanans.
In other words, the premises must'subsume' the explanadum under a law-like regularity that covers the case at hand. These two conditions make it clear why the covering law model is also called the deductive-nomological model: it combines the virtues of deductive logic with the scientific impetus to explain particular phenomena as instances of general laws of nature.
The third and final condition demands that all the premises be actually true; that is, the argument should not only be a possible explanation but should, in fact, be an actual explanation of the explanation and portray the phenomena to be explained as the logically necessary outcome of general laws of nature as they apply to specific circumstances.
The philosophy of science can be taken to be the formulation of worldviews that are consistent with, and in some sense based on, important scientific theories. According to this understanding, the task of the philosopher of science is to elaborate on the broader implications of science. Another conception of the philosophy of science is that it is an exposition of the assumptions and predispositions of scientists.
The philosopher of science may point out that scientists presuppose that nature is not capricious and that there exist in nature regularities of sufficiently low complexity to be accessible to the investigator. A third understanding is that the philosophy of science is a discipline in which the concepts and theories of the sciences are analyzed and clarified.
A fourth view is that the philosophy of science is a second-order sub-discipline where its practitioners seek answers to questions such as:
- What characteristics distinguish scientific inquiry from other types of investigation?
- What procedures should scientists follow in investigating nature?
- What conditions must be satisfied for a scientific explanation to be correct?
- What is the cognitive status of scientific laws and principles?
In an attempt to provide answers to these questions, philosophers of science have emerged with schools and orientations, from the positivist orientation through the critical rationalism of Karl Popper and the philosophy of science of Thomas Kuhn to that of Paul K. Feyerabend. The canonization of the principles, methods, and procedures in science reached its peak in the orientation of the positivist philosophy of science.
In this orientation, science as an enterprise is considered to always begin with observations of natural phenomena stated in observational sentences, put into a cumulative body of statements, subjected to verifications and confirmations, and producing general statements about aspects of the world. These come in the form of hypotheses, theories, and laws—the totality of scientific knowledge.
Science with this orientation is considered the paradigm of rationality, the model of truth, and the standard of knowledge. It is able to make claims about the world that are either true or false, which are usually verified and confirmed for acceptance or non-acceptance. For positivists, scientific knowledge is progressive, cumulative, and linear. The goal of science is to produce explanations about events in the world and, therefore, the truth about aspects of the world.
Karl R. Popper is the arrowhead of the philosophy of science, at the heart of which are conjectures and refutations by falsification. Certain aspects of his discourse are found to be of positivist science, while easy disagreements are noticeable in some other aspects.
For instance, the positivist philosophy of science and Popper's philosophy of science see science as the paradigm of rationality in possession of a given method, with the aim of discovering the truth about the world. Furthermore, both Popper and the Positivist see science as a progressive enterprise. However, whereas the positivist orientation sees scientific enterprise as beginning with observations, followed by verifications and accumulation of data ending in general statements, Karl Popper's position sees science as beginning conjectures (serious guesses) progressing through critical exposition, falsificationism/falsifiability, and refutation when conjectures are falsified.
Thus, whereas the positivist philosophy of science characterizes scientific ventures with features such as pure observations and verification/verifiability, Popper's philosophy of science considers the venture as scientific when its claims are subjected to critical rationalism, jettisoned when refuted by falsification, and progressive with the speculation of a new conjecture, therefore extending the frontiers of knowledge.
The basic propositions of science, for Popper, are taken to be conjectures, which are approximations of the truth about the world and cannot be said to be true or false. Furthermore, while accepting that science is the paradigm of rationality and would continue to seek truth as its goal, it would always miss the truth by a wide margin because, for him, no one knows the truth. He rejects the claims of Descartes that we must not accept any claim to be true except if it is clear and distinct.
For Popper, one cannot be sure whether clarity and distinctness are criteria of truth; what we can be sure about is that obscurity and confusion are indications of error. And so, a valid scientific aim is directed at avoiding error while accepting ignorance.
The philosophy of science has also witnessed other actors, such as Thomas Kuhn, who believes that the characteristic feature of a valid science is the existence of paradigms engaged in revolution. According to him, scientific enterprise usually has certain principles, procedures, precepts, and axioms that constitute paradigms found to guide what is referred to as normal science. When such paradigms are confronted by opposing models and paradigms, crises emerge. With time, the crisis results in a revolution and the overthrow of the reigning paradigm to produce another normal science.
And so, the two ideas that rule the enterprise of science, for Kuhn, are paradigms and revolution. This found expression in the history of science, from the Ptolemaic system through Copernicus and Keplar to Isaac Newton and Albert Einstein to the science of quantum mechanics. The position of Thomas Kuhn is that there cannot be what is referred to as the rationality of science', and neither can science be seen as a paradigm of rationality.
This is so because, throughout the history of science, it has been characterized by different paradigms of rationality. There is no one fixed, universal, cross-contextual, transcendental, or overarching framework of discourse that could be seen as either 'the' scientific method or 'the' rationality of science. It is at this point that we find some overlap between Thomas Kuhn and Paul K. Feyerabend. The latter sees science as a cognitive scheme having the same rights and privileges as voodoo, religion, mysticism, magic, mythology, and philosophy. For Feyerabend, reality is created, just as objectivity and truth are. What we have to engage in within our human condition is a plurality.