Science (from the Latin scientia, meaning "knowledge") is an enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the natural world. According to Aristotle, science is also the resulting body of reliable knowledge that can be logically and convincingly explained (see "History and etymology" section below).
Since classical antiquity science as a type of knowledge was closely linked to philosophy, the way of life dedicated to discovering such knowledge. And into early modern times the two words were sometimes used interchangeably in the English language. By the 17th century, "natural philosophy" (which is today called "natural science") could be considered separately from "philosophy" in general. But "science" continued to also be used in a broad sense denoting reliable knowledge about a topic, in the same way it is still used in modern terms such as library science, political science, and computer science.
The more narrow sense of "science" which is common today, developed as a part of science became a distinct enterprise of defining "laws of nature", based on early examples such as Kepler's laws, Galileo's laws, and Newton's laws of motion. In this period it became more common to refer to natural philosophy as "natural science". Over the course of the 19th century, the word "science" became increasingly strongly associated with the disciplined study of the natural world, for example physics and chemistry. Many of the other areas of scientific study outside the natural sciences have sometimes been classified as social sciences.
Basic classifications
Scientific fields are commonly divided into two major groups: natural sciences, which study natural phenomena (including biological life), and social sciences, which study human behavior and societies. These groupings are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being tested for its validity by other researchers working under the same conditions. There are also related disciplines that are grouped into interdisciplinary and applied sciences, such as engineering and health science. Within these categories are specialized scientific fields that can include elements of other scientific disciplines but often possess their own terminology and body of expertise.
Mathematics, which is classified as a formal science, has both similarities and differences with the natural and social sciences. It is similar to empirical sciences in that it involves an objective, careful and systematic study of an area of knowledge; it is different because of its method of verifying its knowledge, using a priori rather than empirical methods. Formal science, which also includes statistics and logic, is vital to the empirical sciences. Major advances in formal science have often led to major advances in the empirical sciences. The formal sciences are essential in the formation of hypotheses, theories, and laws, both in discovering and describing how things work (natural sciences) and how people think and act (social sciences).
History and etymology
While descriptions of disciplined empirical investigations of the natural world exist from times at least as early as classical antiquity (for example, by Aristotle and Pliny the Elder), and scientific methods have been employed since the Middle Ages (for example, by Alhazen and Roger Bacon), the dawn of modern science is generally traced back to the early modern period during what is known as the Scientific Revolution of the 16th and 17th centuries. This period was marked by a new way of studying the natural world, by methodical experimentation aimed at defining "laws of nature" while avoiding concerns with metaphysical concerns such as Aristotle's theory of causation.
This modern science developed from an older and broader enterprise. The word "science" is from Old French, and in turn from Latin scientia which was one of several words for "knowledge" in that language. In philosophical contexts, scientia and "science" were used to translate the Greek word epistemē, which had acquired a specific definition in Greek philosophy, especially Aristotle, as a type of reliable knowledge which is built up logically from strong premises, and can be communicated and taught. Aristotle's influential emphasis was upon the "theoretical" step of deducing universal rules from raw data, and did not treat the gathering of experience and raw data as part of science itself.
From the Middle Ages to the Enlightenment, science or scientia continued to be used in this broad sense, which was still common until the twentieth century."Science" therefore had the same sort of very broad meaning that philosophy had at that time. In other Latin influenced languages, including French, Spanish, Portuguese, and Italian, the word corresponding to science also carried this meaning.
Prior to the 18th century, the preferred term for the study of nature among English speakers was "natural philosophy", while other philosophical disciplines (e.g., logic, metaphysics, epistemology, ethics and aesthetics) were typically referred to as "moral philosophy". (Today, "moral philosophy" is more-or-less synonymous with "ethics".) Science only became more strongly associated with natural philosophy than other sciences gradually with the strong promotion of the importance of experimental scientific method, by people such as Francis Bacon. With Bacon, begins a more widespread and open criticism of Aristotle's influence which had emphasized theorizing and did not treat raw data collection as part of science itself. An opposed position became common: that what is critical to science at its best is methodical collecting of clear and useful raw data, something which is easier to do in some fields than others.
The word "science" in English was still however used in the 17th century to refer to the Aristotelian concept of knowledge which was secure enough to be used as a prescription for exactly how to accomplish a specific task. With respect to the transitional usage of the term "natural philosophy" in this period, the philosopher John Locke wrote disparagingly in 1690 that "natural philosophy is not capable of being made a science".
Locke's assertion notwithstanding, by the early 19th century natural philosophy had begun to separate from philosophy, though it often retained a very broad meaning. In many cases, science continued to stand for reliable knowledge about any topic, in the same way it is still used today in the broad sense (see the introduction to this article) in modern terms such as library science, political science, and computer science. In the more narrow sense of science, as natural philosophy became linked to an expanding set of well-defined laws (beginning with Galileo's laws, Kepler's laws, and Newton's laws for motion), it became more popular to refer to natural philosophy as natural science. Over the course of the 19th century, moreover, there was an increased tendency to associate science with study of the natural world (that is, the non-human world). This move sometimes left the study of human thought and society (what would come to be called social science) in a linguistic limbo by the end of the century and into the next.
Through the 19th century, many English speakers were increasingly differentiating science (i.e., the natural sciences) from all other forms of knowledge in a variety of ways. The now-familiar expression “scientific method,” which refers to the prescriptive part of how to make discoveries in natural philosophy, was almost unused until then, but became widespread after the 1870s, though there was rarely total agreement about just what it entailed. The word "scientist," meant to refer to a systematically working natural philosopher, (as opposed to an intuitive or empirically minded one) was coined in 1833 by William Whewell.Discussion of scientists as a special group of people who did science, even if their attributes were up for debate, grew in the last half of the 19th century. Whatever people actually meant by these terms at first, they ultimately depicted science, in the narrow sense of the habitual use of the scientific method and the knowledge derived from it, as something deeply distinguished from all other realms of human endeavor.
By the 20th century, the modern notion of science as a special kind of knowledge about the world, practiced by a distinct group and pursued through a unique method, was essentially in place. It was used to give legitimacy to a variety of fields through such titles as "scientific" medicine, engineering, advertising, or motherhood. Over the 20th century, links between science and technology also grew increasingly strong. As Martin Rees explains, progress in scientific understanding and technology have been synergistic and vital to one another.
Richard Feynman described science in the following way for his students: "The principle of science, the definition, almost, is the following: The test of all knowledge is experiment. Experiment is the sole judge of scientific 'truth'. But what is the source of knowledge? Where do the laws that are to be tested come from? Experiment, itself, helps to produce these laws, in the sense that it gives us hints. But also needed is imagination to create from these hints the great generalizations — to guess at the wonderful, simple, but very strange patterns beneath them all, and then to experiment to check again whether we have made the right guess." Feynman also observed, "...there is an expanding frontier of ignorance...things must be learned only to be unlearned again or, more likely, to be corrected.
Scientific method
A scientific method seeks to explain the events of nature in a reproducible way, and to use these findings to make useful predictions. This is done partly through observation of natural phenomena, but also through experimentation that tries to simulate natural events under controlled conditions. Taken in its entirety, a scientific method allows for highly creative problem solving whilst minimizing any effects of subjective bias on the part of its users (namely the confirmation bias).
Basic and applied research
Although some scientific research is applied research into specific problems, a great deal of our understanding comes from the curiosity-driven undertaking of basic research. This leads to options for technological advance that were not planned or sometimes even imaginable. This point was made by Michael Faraday when, allegedly in response to the question "what is the use of basic research?" he responded "Sir, what is the use of a new-born child?". For example, research into the effects of red light on the human eye's rod cells did not seem to have any practical purpose; eventually, the discovery that our night vision is not troubled by red light would lead militaries to adopt red light in the cockpits of all jet fighters. In a nutshell: Basic research is the search for knowledge. Applied research is the search for solutions.
Experimentation and hypothesizing
Based on observations of a phenomenon,scientists may generate a model. This is an attempt to describe or depict the phenomenon in terms of a logical physical or mathematical representation. As empirical evidence is gathered, scientists can suggest a hypothesis to explain the phenomenon. Hypotheses may be formulated using principles such as parsimony (traditionally known as "Occam's Razor") and are generally expected to seek consilience - fitting well with other accepted facts related to the phenomena. This new explanation is used to make falsifiable predictions that are testable by experiment or observation. When a hypothesis proves unsatisfactory, it is either modified or discarded. Experimentation is especially important in science to help establish a causational relationships (to avoid the correlation fallacy). Operationalization also plays an important role in coordinating research in/across different fields.
Once a hypothesis has survived testing, it may become adopted into the framework of a scientific theory. This is a logically reasoned, self-consistent model or framework for describing the behavior of certain natural phenomena. A theory typically describes the behavior of much broader sets of phenomena than a hypothesis; commonly, a large number of hypotheses can be logically bound together by a single theory. Thus a theory is a hypothesis explaining various other hypotheses. In that vein, theories are formulated according to most of the same scientific principles as hypotheses.
While performing experiments, scientists may have a preference for one outcome over another, and so it is important to ensure that science as a whole can eliminate this bias. This can be achieved by careful experimental design, transparency, and a thorough peer review process of the experimental results as well as any conclusions.After the results of an experiment are announced or published, it is normal practice for independent researchers to double-check how the research was performed, and to follow up by performing similar experiments to determine how dependable the results might be.
Philosophy of science
The philosophy of science seeks to understand the nature and justification of scientific knowledge. It has proven difficult to provide a definitive account of scientific method that can decisively serve to distinguish science from non-science. Thus there are legitimate arguments about exactly where the borders are, which is known as the problem of demarcation. There is nonetheless a set of core precepts that have broad consensus among published philosophers of science and within the scientific community at large. For example, it is universally agreed that scientific hypotheses and theories must be capable of being independently tested and verified by other scientists in order to become accepted by the scientific community.
There are different schools of thought in the philosophy of scientific method. Methodological naturalism maintains that scientific investigation must adhere to empirical study and independent verification as a process for properly developing and evaluating natural explanations for observable phenomena. Methodological naturalism, therefore, rejects supernatural explanations, arguments from authority and biased observational studies. Critical rationalism instead holds that unbiased observation is not possible and a demarcation between natural and supernatural explanations is arbitrary; it instead proposes falsifiability as the landmark of empirical theories and falsification as the universal empirical method. Critical rationalism argues for the ability of science to increase the scope of testable knowledge, but at the same time against its authority, by emphasizing its inherent fallibility. It proposes that science should be content with the rational elimination of errors in its theories, not in seeking for their verification (such as claiming certain or probable proof or disproof; both the proposal and falsification of a theory are only of methodological, conjectural, and tentative character in critical rationalism). Instrumentalism rejects the concept of truth and emphasizes merely the utility of theories as instruments for explaining and predicting phenomena.
Biologist Stephen J. Gould maintained that certain philosophical propositions—i.e., 1) uniformity of law and 2) uniformity of processes across time and space—must first be assumed before you can proceed as a scientist doing science. Gould summarized this view as follows: "You cannot go to a rocky outcrop and observe either the constancy of nature's laws nor the working of unknown processes. It works the other way around." You first assume these propositions and "then you go to the outcrop of rock."
Media perspectives
The mass media face a number of pressures that can prevent them from accurately depicting competing scientific claims in terms of their credibility within the scientific community as a whole. Determining how much weight to give different sides in a scientific debate requires considerable expertise regarding the matter. Few journalists have real scientific knowledge, and even beat reporters who know a great deal about certain scientific issues may know little about other ones they are suddenly asked to cover.
