William James, answered from the texts and cited to the page.
Radical empiricism is my name for a Weltanschauung — a whole philosophical outlook — that begins where ordinary empiricism begins but refuses to stop where ordinary empiricism stops.1 The ordinary empiricist tradition, from Hume through the associationists, laid its stress on the parts, the elements, the individual facts, and treated wholes as collections and universals as abstractions.1
So far I follow. But that tradition showed a persistent tendency to do away with the connections between things — to insist on disjunction, separateness, the loose-and-separate character of experienced items — while treating relations as somehow less real than the terms they connect.1 Berkeley's nominalism, Hume's famous declaration that whatever things we distinguish are as loose and separate as if they had no manner of connection, the general pulverization of experience by the mind-dust theory — these are the symptoms of what I mean.1
My departure from that tradition is stated in a single principle: to be radical, an empiricism must neither admit into its constructions any element that is not directly experienced, nor exclude from them any element that is directly experienced.2 The relations that connect experiences must themselves be experienced relations; and any kind of relation experienced must be accounted as real as anything else in the system.2
This is the move that ordinary empiricism refuses to make — and it is the move that changes everything. For consider what experience actually delivers. Relations of time, space, difference, likeness, change, cause — these are just as integral members of the sensational flux as the terms they relate; conjunctive relations are just as true members of the flux as disjunctive ones.3
Green's intellectualism manufactured atomistic, unrelated sensations as a premise, and then fled to transcendental idealism when the atoms proved unable to cohere — but those unrelated atoms were purely fictitious products of the rationalist fancy, not what sensible life in concreto actually shows.3 The world that radical empiricism represents is a collection, some parts of which are conjunctively and others disjunctively related.4
Two parts, themselves disjoined, may hang together by intermediaries with which they are severally connected — and the whole world eventually may hang together similarly, inasmuch as some path of conjunctive transition by which to pass from one part to another may always be discernible.4 I call this concatenated union, to distinguish it from the "through-and-through" type of union — each in all and all in each — that monistic systems demand when things are taken in their absolute reality.4
The absolute idealists want total conflux; experience delivers partial conflux, contiguousness, likeness, nearness, simple with-ness, and sometimes mere and-ness.4 The thesis, stated most nakedly, is this: there is no fact not actually experienced to be such.5 The concept of being is not wider than or prior to the concept of content of experience.5
That is a strong claim, and I will not pretend it is without difficulties — writing to my friend Miller in 1905 I confessed to being much boggled and muddled about certain consequences of it, particularly about how to speak of two experiences standing in relations whose relational character is not itself a content of either experience.5 All the hoary errors of philosophy are based on something pretty inevitable in the structure of our thinking, and I distrust summary executions.5
But the upshot is clear enough. Reality is plural, concatenated, felt in its conjunctions as much as its disjunctions, and philosophy that excludes the experienced relations from its account of what is real has already departed from what experience delivers — not toward greater rigor, but toward a fiction it then needs an Absolute to repair.
Empiricism, on the contrary, lays the explanatory stress upon the part, the element, the individual, and treats the whole as a collection and the universal as an abstraction... It is essentially a mosaic philosophy, a philosophy of plural facts, like that of Hume and his descendants.Essays in Radical Empiricism, pp. 41–44
To be radical, an empiricism must neither admit into its constructions any element that is not directly experienced, nor exclude from them any element that is directly experienced. For such a philosophy, the relations that connect experiences must themselves be experienced relations, and any kind of relation experienced must be accounted as 'real' as anything else in the system.Essays in Radical Empiricism, pp. 41–44
Every examiner of the sensible life in concreto must see that relations of every sort, of time, space, difference, likeness, change, rate, cause, or what not, are just as integral members of the sensational flux as terms are, and that conjunctive relations are just as true members of the flux as disjunctive relations are... But the atomistic and unrelated sensations which he had in mind were purely fictitious products of his rationalist fancy.A Pluralistic Universe, p. 24
Radical empiricism takes conjunctive relations at their face value, holding them to be as real as the terms united by them. The world it represents as a collection, some parts of which are conjunctively and others disjunctively related... Such determinately various hanging-together may be called concatenated union, to distinguish it from the 'through-and-through' type of union, 'each in all and all in each'... which monistic systems hold to obtain when things are taken in their absolute reality.Essays in Radical Empiricism, pp. 107–109
What I mean by it is the thesis that there is no fact 'not actually experienced to be such.'... I am much boggled and muddled; and the total upshot with me is to see that all the hoary errors and prejudices of man in matters philosophical are based on something pretty inevitable in the structure of our thinking, and to distrust summary executions by conviction of contradiction.The Letters of William James Vol II, pp. 235–237