A History of Philosophy | 74 Bertrand Russell -- Logical Atomism

19th century empiricism can be characterized by three features: first, the development of the hypothetical-deductive method in science as a replacement for foundationalist first principles; second, the extension of this method from natural science into the social sciences and study of human behavior, creating the unity of science movement; third, the development of a phenomenalist position that rejects metaphysics and describes matter and mind in purely empirical terms as the permanent possibility of sensations and reflections.

“19th century empiricism can be characterized in these three ways first of all the development of the hypothetical deductive method in science”

Russell wrote an early work titled 'Mysticism and Logic' in which he argued against methodologies rooted in Hegel, Bergson, and Bradley, which claimed intuitive knowledge of the whole or immediate awareness of being in its totality, because Russell does not believe there are any internal relationships between atomic facts that would ground such mystical intuition.

“one of his first books was called mysticism and logic in which in arguing for his logical method he repudiated the methodology of people like Baron Sun and Bradley rooted in Hegel Bergson you recall talked of an intuition that we have of the whole sea out of which a worldview arises and Bradley speaks of an immediate awareness of being in its large scope which gives structure to the detailed work we do one particular rustle calls that mysticism repudiates it completely because he does not think that there are any internal relationships between the atomic facts”

Russell's Human Knowledge (1947-48) attempted to organize scientific knowledge through deduction but discovered that direct empirical verification of generalizations provides insufficient premises for complete deductive explanation of scientific knowledge, forcing him to introduce additional non-empirical premises he called scientific postulates.

“he came to the realization that if he wanted to do this by deduction from empirical generalizations of which we have certain direct empirical verification that is to say samples that we can verify that we don't have enough premises to achieve the deduction in other words scientific knowledge has to involve additional hypotheses then simply hypotheses which are amenable to any kind of direct verification he admits therefore that pure empiricism does not provide logical explanation that we have to introduce additional premises that he calls scientific postulates”

Logical atomism is the thesis that all thought, belief, knowledge, and discourse on any subject whatsoever can and should be analyzed into atomic propositions and organized into a formal deductive system.

“what is logical well it's the the thesis that all of our thought beliefs knowledge all of our discourse in on any subject whatsoever can and should be analyzed in two atomic propositions”

William James's searchlight theory of consciousness proposes that consciousness is like a searchlight illuminating a chain of physical events; a mental event occurs at the point where the searchlight lights upon the physical event, making that single event both physical and mental simultaneously, exemplifying neutral monism.

“William James had this this notion and he explained in what he called the searchlight theory of consciousness that is to say what you have to do is to picture something going along like that let's say it's a chain of physical events which is lit up at this point by searchlight yeah that is to say consciousness is aroused you'll see when the luck when you light upon that catch the plane in the searchlight so that this one event at that juncture is both a physical event and a mental event”

Russell initially accepted intentionality—the view that consciousness is a mental act that intends or points to an object—as a reason for being a realist; however, he later came to reject both intentionality and knowledge of causal connections, leading him to become a phenomenalist.

“in his earliest work he had an additional reason for being a realist as he was namely he accepted the notion that consciousness has intentionality that it is a mental act that intends points means an object yes he and in as much as intentionality the mental Act gives to me an object Russell started out as a realist but he came to reject them intellect and he came to reject knowledge of causal connections therefore he became a phenomenal”

Mill defined matter phenomenalistically as the permanent possibility of sensations and mind as the permanent possibility of reflections, providing purely empirical definitions with no claims about what matter or mind are in themselves.

“matter is simply described defined in phenomena list terms as the further possibility of sensations then mind is the permanent possibility of reflections is a purely empirical definitions phenomena list definitions nothing about what mind is in itself what matter is in itself”

Atomic propositions consist of terms (which refer either to general properties like 'blue' or 'square' or to particular individuals via proper names) and predicates, and are the smallest units of thought; molecular propositions are combinations of atomic propositions.

“admittedly atomic propositions are not the smallest parts of speech because a proposition has a predicate subject and a predicate so in addition to atomic propositions there are terms that of course terms don't mean anything except as they are used in asserting something or denying something and that is to say in propositions so you have terms you have atomic propositions atomic propositions combine to form molecular propositions”

Russell's theory distinguishes between knowledge by acquaintance (direct knowledge of sense data and one's own mental states) and knowledge by description (knowledge of complex entities like the present King of France described via molecular propositions), with the latter being mental constructs based on the former.

“he makes a distinction between knowledge knowledge by acquaintance and knowledge by description knowledge by acquaintance his knowledge of since data knowledge of our own mental states knowledge by description is knowledge of material objects like the present King of France and those are mental constructs that we describe”

The positivist movement shaped by Russell, Wittgenstein, and others in 20th-century analytic philosophy—including figures like Carnap and Quine—has been the most influential philosophical movement in the West in the 20th century, specifically a scientific naturalism oriented to the methodology and findings of natural science.

“shaping the development of what has perhaps been the most influential philosophical movement in the West in the 20th century scientific naturalism okay a naturalistic philosophy oriented to the methodology and findings of natural science”

Russell's initial mathematical interest led him to cooperate with Whitehead at Cambridge on Principia Mathematica (PM), showing that mathematics is essentially the same as logic—both are formal deductive systems with axioms, theorems, and symbolic logic for handling subject matter.

“he started out as a mathematician cooperated with Whitehead when they were both at Cambridge cooperated with Whitehead in writing principia mathematica”