The phrase “nature of science” typically refers to the values and assumptions inherent to scientific knowledge and the development of scientific knowledge. Although there are disagreements about specific aspects of nature of science, we have chosen to focus only on those aspects that are generally agreed upon, accessible to K-12 students, and important for all citizens to know.
Project ICAN, therefore, focuses on the following: scientific knowledge is tentative (subject to change), empirically-based (based on and/or derived from observations of the natural world), subjective (theory-laden), necessarily involves human inference, imagination, and creativity (involves the invention of explanations), and is socially and culturally embedded. Two additional important aspects are the distinction between observations and inferences, and the functions of, and relationships between scientific theories and laws. What follows is a brief discussion of these characteristics of science and scientific knowledge.
First, students should be aware of the crucial distinction between observation and inference. Observations are descriptive statements about natural phenomena that are “directly” accessible to the senses (or extensions of the senses) and about which several observers can reach consensus with relative ease. For example, objects released above ground level tend to fall and hit the ground. By contrast, inferences are statements about phenomena that are not “directly” accessible to the senses. For example, objects tend to fall to the ground because of “gravity.” The notion of gravity is inferential in the sense that it can only be accessed and/or measured through its manifestations or effects.
Second, closely related to the distinction between observations and inferences is the distinction between scientific laws and theories. Laws are statements or descriptions of the relationships among observable phenomena. Boyle’s law, which relates the pressure of a gas to its volume at a constant temperature, is a case in point. Theories, by contrast, are inferred explanations for observable phenomena. The kinetic molecular theory, which explains Boyle’s law, is one example. Scientists do not usually formulate theories in the hope that one day they will acquire the status of “law.” Theories and laws are both very important to science and they are different types of knowledge. Theories do not mature into laws and laws do not mature into theories.
Third, all scientific knowledge is, at least partially, based on and/or derived from observations of the natural world (i.e., empirical). All of the theories and laws developed by scientists must be checked against what actually occurs in the natural world. If the empirical observations are not consistent with the predictions derived from our theories and laws, scientists begin to search for alternative descriptions and explanations (i.e., laws and theories).
Fourth, although scientific knowledge is empirically-based, it nevertheless involves human imagination and creativity. Science involves the invention of explanations and this requires a great deal of creativity by scientists. This aspect of science, coupled with its inferential nature, entails that scientific concepts, such as atoms, black holes, and species, are functional theoretical models rather than faithful copies of reality.
Fifth, scientific knowledge is subjective or theory-laden. Scientists’ theoretical commitments, beliefs, previous knowledge, training, experiences, and expectations actually influence their work. All these background factors form a mind-set that affects the problems scientists investigate and how they conduct their investigations, what they observe (and do not observe), and how they make sense of, or interpret their observations.
Sixth, science affects and is affected by the various elements and contexts of the culture in which it is practiced. These elements include, but are not limited to, social fabric, power structures, politics, socioeconomic factors, philosophy, and religion. In short, we say that science is socially and culturally embedded.
Seventh, it follows from the previous discussions that scientific knowledge is never absolute or certain. This knowledge, including “facts,” theories, and laws, is tentative and subject to change. Scientific claims change as new evidence, made possible through advances in theory and technology, is brought to bear on existing theories or laws, or as old evidence is reinterpreted in the light of new theoretical advances or shifts in the directions of established research programs.