- For the scientific journal named Science, see Science (journal).
Science refers to either:
Areas of science may be classified in two major dimensions:
What is science?
There are different theories of what "science" is.
According to empiricism, "scientific" theories are objective, empirically verifiable, and "predictive" — they predict empirical results that can be checked and possibly contradicted.
In contrast, scientific realism defines science in terms of ontology: science attempts to identify what "things" in the world, their causal powers, the mechanisms through which they exercise those powers, and the sources of those powers in terms of the thing's structure or internal nature.
Even in the empiricist tradition, we must be careful to understand that "prediction" refers to the outcome of an experiment or study, rather than to literally predicting the future. For example, to say, "a paleontologist may make predictions about finding a certain type of dinosaur" is consistent with the empiricist's use of prediction. On the other hand, sciences like geology or meteorology need not be able to make accurate predictions about earthquakes or the weather to qualify as sciences. Empiricist philosopher, Karl Popper also argued that certain verification is impossible and that scientific hypotheses can only be falsified (falsification).
Positivism, a form of empiricism, advocates using science, as defined by empiricism, to govern human affairs. Because of their close affiliation, the terms "positivism" and "empiricism" are often treated as interchangable terms. Both have been subjected to devastating criticisms.
W. V. Quine demonstrated the impossibility of a theory-independent observation language, so the very notion of testing theories with facts is problematic.
- Observations are always theory-laden. Thomas Kuhn demonstrated that science always involves "paradigms," sets of (often unstated) assumptions, rules, practices, etc. and that transitions from one paradigm to another generally does not involve verification or falsification of scientific theories. Moreover, he demonstrated that science has not proceeded historically as the steady accumulation of facts, as the empiricist model implies.
- Philosopher Roy Bhaskar  has shown that the practice of scientific experiments presumes a "layered" ontology in which empirical reality is only the most evident layer, but there must also be actual and real layers. According to Bhaskar, science is knowledge of the real, and empiricism makes a crucial error of reasoning — the epistemic fallacy. This is the mistake of confusing the limits of human knowledge with the limits of reality itself.
For more information, see Theories and sociology of the history of science.
Some counter-intuitive findings
Some of the findings of science can be very counter-intuitive. Atomic theory, for example, implies that a granite boulder which appears a heavy, hard, solid, grey object is actually a combination of subatomic particles with none of these properties, moving very rapidly in an area consisting mostly of empty space. Many of humanity's preconceived notions about the workings of the universe have been challenged by new scientific discoveries. Work in psychology has suggested that some of the reasons for this counter-intuition may be that our brains are developed in order to deal with the world in a very specific fashion, one which has little regard for atoms and other extreme micro- or macroscopic phenomena (but explaining how we regard science by the use of science is somewhat inherently problematic).
Scientific models, theories and laws
Main article: scientific method
The terms "model", "hypothesis", "theory" and "law" have different meanings in science than in colloquial speech. Scientists use the term model to mean a description of something, specifically one which can be used to make predictions which can be tested by experiment or observation. A hypothesis is a contention that has not (yet) been either well supported nor ruled out by experiment. A physical law or a law of nature is a scientific generalization based on empirical observations.
The word theory is misunderstood particularly often by laymen. The common usage of the word "theory" refers to ideas that have no firm proof or support; in contrast, scientists usually use this word to refer to bodies of ideas that make specific predictions. To say "the apple fell" is to state a fact, whereas Newton's theory of universal gravitation is a body of ideas that allows a scientist to explain why the apple fell and make predictions about other falling objects.
An especially fruitful theory that has withstood the test of time and has an overwhelming quantity of evidence supporting it is considered to be "proven" in the scientific sense. Some universally accepted models such as heliocentric theory and atomic theory are so well-established that it is impossible to imagine them ever being falsified. Others, such as relativity, electromagnetism and biological evolution have survived rigorous empirical testing without being contradicted, but it is nevertheless conceivable that they will some day be supplanted. Younger theories such as string theory may provide promising ideas, but have yet to receive the same level of scrutiny.
Scientists never claim absolute knowledge. Unlike a mathematical proof, a "proven" scientific theory is always open to falsification if new evidence is presented. Even the most basic and fundamental theories may turn out to be imperfect if new observations are inconsistent with them.
Newton's law of gravitation is a famous example of a law which was found not to hold in experiments involving motion at speeds close to the speed of light or in close proximity to strong gravitational fields. Outside those conditions, Newton's Laws remain an excellent model of motion and gravity. Because general relativity accounts for all of the phenomena that Newton's Laws do, and more, general relativity is now regarded as a better theory.
Philosophy of science
Main article: Philosophy of science
Science's effectiveness has made it a subject of much philosophical speculation. The philosophy of science seeks to understand the nature and justification of scientific knowledge, and its ethical implications. It has proved remarkably difficult to provide an account of the scientific method that can serve to distinguish science from non-science.
Mathematics and the scientific method
Mathematics is essential to many sciences. The most important function of mathematics in science is the role it plays in the expression of scientific models. Observing and collecting measurements, as well as hypothesizing and predicting, often require mathematical models and extensive use of mathematics. Mathematical branches most often used in science include calculus and statistics, although virtually every branch of mathematics has applications, even "pure" areas such as number theory and topology. Mathematics is most prevalent in physics, but less so in chemistry, biology, and some social sciences.
Some thinkers see mathematicians as scientists, regarding physical experiments as inessential or mathematical proofs as equivalent to experiments. Others do not see mathematics as a science, since it does not require experimental test of its theories and hypotheses. In either case, the fact that mathematics is such a useful tool in describing the universe is a central issue in the philosophy of mathematics.
See: Eugene Wigner, The Unreasonable Effectiveness of Mathematics in the Natural Sciences.
Richard Feynman said "Mathematics is not real, but it feels real. Where is this place?", while Bertrand Russell's favourite definition of mathematics was "the subject in which we never know what we are talking about nor whether what we are saying is right."
Goals of science
Despite popular impressions of science, it is not the goal of science to answer all questions. The goal of the physical sciences is to answer only those that pertain to physical reality. Also, science cannot possibly address all possible questions, so the choice of which questions to answer becomes important. Science does not and can not produce absolute and unquestionable truth. Rather, physical science often tests hypotheses about some aspect of the physical world, and when necessary revises or replaces it in light of new observations or data.
According to empiricism, science does not make any statements about how nature actually "is"; science can only make conclusions about our observations of nature. Of course, if people really believed this, they would be foolish to trust sciences such as medicine with their lives. Both scientists and the people who accept science believe, and more importantly, act as if nature actually "is" as science claims. The developments of quantum mechanics in the early 20th century showed that observations are not independent of interactions, and the implications of wave-particle duality have challenged the traditional notion of "objectivity" in science. Still, this is only a problem if we accept the empiricist notion of science. How nature really "is" does not depend on our ability to observe it, with or without our observations affecting it.
Science is not a source of subjective value judgements, though it can certainly speak to matters of ethics and public policy by pointing to the likely consequences of actions. However, science can't tell us which of those consequences to desire or which is 'best'. What one projects from the currently most reasonable scientific hypothesis onto other realms of interest is not a scientific issue, and the scientific method offers no assistance for those who wish to do so. Scientific justification (or refutation) for many things is, nevertheless, often claimed. Of course, value judgements are intrinsic to science itself. For example, science values truth and knowledge.
Individualism is a tacit assumption underlying most empiricist accounts of science. They treat science as if it were purely a matter of a single individual confronting nature, testing and predicting hypotheses. In fact, science is always a collective activity conducted by a scientific community. This can be demonstrated many ways, perhaps the most fundamental and trivial of which is that scientific results must be communicated with language. Thus the values of scientific communities permeate the science they produce.
Locations of science
Science is practiced in universities and other scientific institutes as well as in the field; as such it is a solid vocation in academia, but is also practiced by amateurs, who typically engage in the observational part of science.
Workers in corporate research laboratories also practice science, although their results are often deemed trade secrets and not published in public journals. Corporate and university scientists often cooperate, with the university scientists focusing on basic research and the corporate scientists applying their findings to a specific technology of interest to the company.
The methods of science are also practiced in many places to achieve specific goals. For example:
- Quality control in manufacturing facilities (for example, a microbiologist in a cheese factory ensures that cultures contain the proper species of bacteria)
- Obtaining and processing crime scene evidence (forensics)
- Monitoring compliance with environmental laws
- Performing medical tests to help physicians evaluate the health of their patients
- Investigating the causes of a disaster (such as a bridge collapse or airline crash)
Fields of science
Holistic, interdisciplinary, and applied sciences
The word science comes from the Latin word, scientia, which means knowledge.
Until the Enlightenment, the word science (or its Latin cognate) meant any systematic or exact, recorded knowledge. Science therefore had the same sort of very broad meaning that philosophy had at that time.
There was a distinction between, for example, "natural science" and "moral science," which later included what we now call philosophy, and this mirrored a distinction between "natural philosophy" and "moral philosophy." More recently, "science" has come to be restricted to what used to be called "natural science" or "natural philosophy." Natural science can be further broken down into physical science and biological science. Social science is often included in the field of science as well.
Fields of study are often distinguished in terms of "hard sciences" and "soft sciences," and these terms (at times considered derogatory) are often synonymous with the terms natural and social science (respectively). Physics, chemistry, biology and geology are all forms of "hard sciences". Studies of anthropology, history, psychology, and sociology are sometimes called "soft sciences." Proponents of this division use the arguments that the "soft sciences" do not use the scientific method, admit anecdotal evidence, or are not mathematical, all adding up to a "lack of rigor" in their methods. Opponents of the division in the sciences counter that the "social sciences" often make systematic statistical studies in strictly controlled environments, or that these conditions are not adhered to by the natural sciences either (for example, behavioral biology relies upon fieldwork in uncontrolled environments, astronomy cannot design experiments, only observe limited conditions). Opponents of the division also point out that each of the current "hard sciences" suffered a similar "lack of rigor" in its own infancy.
The term "science" is sometimes pressed into service for new and interdisciplinary fields that make use of scientific methods at least in part, and which in any case aspire to be systematic and careful explorations of their subjects, including computer science, library and information science, and environmental science. Mathematics and computer science reside under "Q" in the Library of Congress classification, along with all else we now call science.