Philosophy of science is a sub-field of philosophy concerned with the foundations, methods, and implications of science. The central questions of this study concern what qualifies as science, the reliability of scientific theories, and the ultimate purpose of science. This discipline overlaps with metaphysics, ontology, and epistemology, for example, when it explores the relationship between science and truth. While philosophical thought pertaining to science dates back at least to the time of Aristotle, philosophy of science emerged as a distinct discipline only in the middle of the 20th century in the wake of the logical positivism movement, which aimed to formulate criteria for ensuring all philosophical statements' meaningfulness and objectively assessing them. Thomas Kuhn's landmark 1962 book The Structure of Scientific Revolutions was also formative, challenging the view of scientific progress as steady, cumulative acquisition of knowledge based on a fixed method of systematic experimentation and instead arguing that any progress is relative to a "paradigm," the set of questions, concepts, and practices that define a scientific discipline in a particular historical period. Karl Popper and Charles Sanders Pierce moved on from positivism to establish a modern set of standards for scientific methodology.
Dictionaries are most often collections of words in one or more specific languages, usually arranged in alphabetical order, providing information like word meanings, usage, etymology, and, when they contain more than one language, translations. Some dictionaries include information more commonly found in encyclopedias. Encyclopedias are collections of information on terms, figures, eras, locations also arranged alphabetically, and, alongside definitions of terms, they also include more in-depth general information on a topic. Encyclopedias can be general or subject-specific.
Biography provides a description of a person's life, detailing the basic facts like birth and death, education, family background, etc. but also portraying the individual subject's experience of those life events.