Philosophy of science
What happened in analytic philosophy of science over the course of the twentieth century?
The twentieth century was an extraordinary period of conceptual upheaval in how science was regarded. There was a rejection of hard-core logical positivism, beginning with Hans Reichenbach (1891-1953). Just as metaphysics and epistemology drew closer to the actual sciences, philosophy of science itself began to look more humanistic as traditional inductive confidence in objective facts was first dislodged by Karl Popper (1902-1994). Thomas S. Kuhn (1922-1996) then inverted the relationship between facts and theories with his notion of a paradigm and scientific revolutions.
Over the same time period, any lingering hopes in "vitalism" or some non-objective life force were put to rest by James D. Watson and Francis Crick's discovery of the double helix structure of DNA. However, the mapping of the human genome at the turn of the twenty-first century did provoke more nuanced views on biological determinism, opening the possibility of a new philosophy of science of biology.
Who was Hans Reichenbach?
Hans Reichenbach (1891-1953) was the leader of "logical empiricism." He was born in Hamburg and studied mathematics, physics, logic, and philosophy. He became a professor of philosophy of science at the University of Berlin and was a close associate of Albert Einstein. He founded Erkenntnis with Rudolf Carnap (1891-1970), which was the premier journal of scientific philosophy in the 1930s.
As with thousands of other Jews at the time, Reichenbach had to leave Germany in 1933. He first went to Istanbul before settling down at the University of California at Los Angeles. His main works include Experience and Prediction (1938), The Theory of Probability (1939-1949), and the posthumous The Direction of Time (1956).
What was Reichenbach's theory of logical empiricism?
Reichenbach disagreed with the logical atomists and logical positivists, who felt that objects of scientific study could be described as if they were made up of sense data. His own realist view became known as physicalism. He argued on pragmatic grounds for a probabilistic interpretation of induction, so that induction could be expressed in terms of probabilities of future events based on the occurrence of these events in the past.
Reichenbach also developed a triple-valued logic in which statements could be true, false, or indeterminate, for quantum theory. He added the option of "indeterminate" to "true" and "false." Quantum theory specifies that some events could not be determined even though their causes were known, so it was important to add indeterminacy to a system of formal logical notation. Although much of his work is highly technical, his The Rise of Scientific Philosophy (1951) is a clear and somewhat generalist account of his perspective.
How did ideas about life change when it came to the philosophy of science?
Many notions of a mysterious "vitalism," or "life force," at the heart of the reproduction of living beings were exchanged for materialist (physical) accounts after James Watson and Francis Crick discovered the double helix in 1953. Watson and Crick's discovery of the structure of DNA took the mystery out of the idea of life because it could account for the reproduction of genetic material in purely chemical terms. The double helix was a three-dimensional model of the twisted-ladder structure of deoxyribonucleic acid (DNA), which showed how sequences of acids and bases would replicate themselves through chemical reactions. Watson and Crick's discovery paved the way for gene-based studies in heredity, culminating in the "mapping" of the human genome (totality of genes) by the early twenty-first century.