The Problems of Philosophy
The Problems of Philosophy is Bertrand Russell’s concise introduction to central issues in epistemology and metaphysics, asking how, if at all, we can have knowledge of a mind-independent world. Beginning from the distinction between appearance and reality, Russell analyzes sense-data, physical objects, universals, induction, a priori knowledge, and the nature of truth. He argues for a critical realism that grants the existence of an external world while insisting that our access to it is mediated and partial. The book also contrasts knowledge by acquaintance and knowledge by description, clarifies the logical structure of propositions, and concludes with reflections on the value of philosophy as an enlargement of the mind.
At a Glance
- Author
- Bertrand Russell
- Composed
- 1911–1912
- Language
- English
- Status
- original survives
- •From appearance to a mind-independent reality: Starting with the instability and subjectivity of sense-data (e.g., color, shape from different viewpoints), Russell argues that we are nonetheless rationally justified in believing in a world of physical objects that cause our experiences, even though these objects are never immediately given in experience.
- •Distinction between sense-data and physical objects: Russell claims that what is directly given in perception are sense-data (colors, sounds, textures), while physical objects are logical constructions or inferred entities postulated to explain the coherence and persistence of these data; this underpins a form of critical realism rather than naive realism.
- •Knowledge by acquaintance vs. knowledge by description: Russell draws a fundamental epistemic distinction between direct, non-inferential awareness (acquaintance) of sense-data, universals, and possibly the self, and indirect, inferential knowledge (description) of ordinary physical objects and other minds, arguing that all knowledge of things not immediately given depends on descriptive reference grounded in acquaintance.
- •Analysis of a priori knowledge and universals: Russell defends the reality of universals (such as similarity, diversity, and relations) and holds that some knowledge—especially in logic and mathematics—is a priori and concerns these abstract entities rather than mere psychological facts, thereby resisting empiricist reductions of necessary truths to habits of expectation.
- •Correspondence theory of truth and the role of judgment: Russell maintains that propositions are complex entities whose truth consists in a structural correspondence with facts in the world; judgments are mental acts that relate the knowing subject to propositions, and error arises when a proposition judged does not correspond to any existing fact.
The book has become a classic of early analytic philosophy and one of Russell’s most widely read works, shaping generations of students’ first encounters with epistemology and metaphysics; its formulations of sense-data theory, knowledge by acquaintance versus description, and the correspondence theory of truth significantly influenced later analytic debates, even among philosophers who rejected aspects of Russell’s realism or theory of universals.
1. Introduction
The Problems of Philosophy (1912) is a short treatise in which Bertrand Russell sets out, in non-technical form, a selection of issues he regarded as central to epistemology and metaphysics. Rather than offering a historical survey, Russell organizes the book around a sequence of interlocking problems: how appearances relate to reality, how we know anything about a mind‑independent world, what kinds of things universals and propositions are, and what distinguishes knowledge from error.
The work begins from everyday perception—the familiar example of a table whose color, shape, and texture shift with lighting and perspective—and develops a distinction between what is immediately given in experience and what is inferred. From this starting point Russell formulates a version of critical realism: the view that there is a world independent of our minds, but that our access to it is mediated by sense-data and by logical inference.
Within this framework, Russell introduces several distinctions that became influential in analytic philosophy, notably between knowledge by acquaintance and knowledge by description, between a priori and empirical knowledge, and between particulars and universals. These distinctions support his account of how humans can have knowledge of both concrete objects and abstract entities such as numbers, relations, and logical principles.
The book also articulates a correspondence theory of truth, according to which propositions are true when they correspond to facts, and false when they do not. Alongside this semantic thesis, Russell investigates the structure of judgment, the status of induction and probability, and the limits of what philosophical inquiry can securely establish.
Although designed as an introduction for students and general readers, The Problems of Philosophy has often been treated as a concise statement of Russell’s mature early views on knowledge and reality, and as a formative text in the development of analytic philosophy in the twentieth century.
2. Historical and Intellectual Context
Russell in Early 20th‑Century Philosophy
When The Problems of Philosophy appeared in 1912, British philosophy was undergoing a transition from late nineteenth‑century British Idealism to the emerging analytic movement. Russell, together with G. E. Moore, had already criticized idealists such as F. H. Bradley and Bernard Bosanquet for what they saw as monistic metaphysics and obscurity of method. The book reflects this shift by privileging logical clarity, argument by analysis, and attention to language.
Key Background Currents
Several intellectual developments form the backdrop to Russell’s treatment of knowledge and reality:
| Background Current | Relevance to the Book |
|---|---|
| British Idealism | Provides the target for Russell’s critique of views that treat reality as fundamentally mental or spiritual. |
| Empiricism (Locke, Hume) | Supplies the emphasis on perception and experience; Russell reworks empiricist themes about ideas, impressions, and induction. |
| Kantian Philosophy | Shapes Russell’s concern with a priori knowledge and the conditions of possible experience, although he rejects Kant’s idealism. |
| New Logic and Mathematics | Work with Whitehead on Principia Mathematica informs Russell’s interest in logical form, propositions, and the structure of scientific knowledge. |
| Scientific Realism | Advances in physics and the prestige of science inform his attempt to reconcile common‑sense beliefs with a more abstract, scientific conception of matter. |
Relation to Contemporary Debates
The book intervenes in several contemporary debates:
- Over the existence and nature of matter, against both Berkeleyan idealism and more radical forms of phenomenalism.
- Over the status of logic and mathematics, where Russell sides with those who treat them as objective and necessary, in contrast to psychologistic accounts.
- Over the foundations of science, especially the justificatory status of inductive reasoning and probabilistic belief.
Later commentators have emphasized the way the text simultaneously inherits early modern problems (such as skepticism and the appearance–reality distinction) and anticipates central themes of analytic philosophy: the analysis of language, logical form, and the ontology of abstract entities.
3. Author and Composition
Russell at the Time of Writing
Bertrand Russell (1872–1970) was already an established figure in logic and the foundations of mathematics when he wrote The Problems of Philosophy. Having co‑authored Principia Mathematica with Alfred North Whitehead and published technical papers on logic and set theory, Russell turned increasingly to presenting his ideas to a wider audience and to addressing traditional philosophical questions with the new tools of logical analysis.
Around 1911–1912, Russell’s philosophical position included:
- A commitment to logical atomism, the view that the world consists of independent facts mirrored by logically structured propositions.
- A developing realism about both the external world and abstract entities (universals).
- A continuing engagement with, and rejection of, the idealism that had dominated his early education at Cambridge.
Circumstances and Aims of Composition
The book was commissioned as part of an early series of accessible philosophical introductions published by Williams and Norgate. Russell composed it rapidly in 1911–1912, drawing on material from his lectures to undergraduates and from more technical writings, but recasting these in non‑symbolic, discursive form.
Proponents of a pedagogical reading emphasize Russell’s stated aim: to present “some problems” rather than an exhaustive system, focusing on issues he thought especially fundamental and tractable for beginning students. Some scholars, by contrast, treat the work as a compact but programmatic statement of Russell’s overall philosophical outlook at that moment.
Relation to Other Works by Russell
The Problems of Philosophy stands in between earlier critiques of idealism (such as “On Denoting” and The Principles of Mathematics) and later developments of logical atomism (for example, in his 1918–1919 lectures). It shares doctrines with:
- The Principles of Mathematics (1903): realism about logic and mathematics, correspondence conception of truth.
- Essays like “On Denoting” (1905): the distinction between acquaintance and description that is central to the book’s epistemology.
Interpreters often read The Problems of Philosophy as capturing a relatively stable phase in Russell’s thought before later shifts in his views on perception, sense-data, and the nature of propositions.
4. Structure and Organization of the Work
The Problems of Philosophy is organized into fifteen short chapters, each addressing a specific cluster of issues, but arranged so that conclusions from earlier chapters provide premises for later ones.
Overall Progression
The sequence can be schematically represented as follows:
| Chapters | Main Focus | Role in the Book |
|---|---|---|
| 1–4 | Appearance, matter, and idealism | Establish the basic epistemic problem and argue for a mind‑independent world. |
| 5 | Acquaintance vs. description | Introduce key epistemological distinctions about how we know objects. |
| 6–8 | Induction and a priori knowledge | Analyze empirical reasoning and defend the possibility of non‑empirical knowledge. |
| 9–11 | Universals and intuitive knowledge | Develop the ontology of abstract entities and our access to them. |
| 12–13 | Truth, error, and probability | Examine the nature of propositions, truth, and the gradations between certainty and opinion. |
| 14–15 | Limits and value of philosophy | Reflect on the scope and significance of philosophical inquiry. |
Thematic Grouping
-
Epistemology of Perception (Chs. 1–4)
Starts from the table example, distinguishes appearance from reality, examines arguments for and against the existence of matter, and critiques idealism. -
Theory of Knowledge (Chs. 5–8, 11, 13)
Introduces knowledge by acquaintance and knowledge by description, discusses induction, general principles, a priori knowledge, intuitive knowledge, and the notions of knowledge, error, and probable opinion. -
Metaphysics of Abstract Objects (Chs. 9–10, 12)
Develops a realist view of universals, analyzes propositions and facts, and articulates a correspondence theory of truth and a theory of judgment. -
Reflexive Chapters on Method and Value (Chs. 14–15)
Consider the limits of philosophical knowledge and the value of philosophy.
The structure is cumulative: Russell moves from the most immediate experiences (perceptual appearances) outward to general principles, abstract entities, and methodological reflections. Each chapter is relatively self‑contained yet presupposes distinctions and results established earlier in the book.
5. Appearance, Reality, and the Problem of Matter
Russell opens the book by contrasting appearance—how things seem in perception—with reality—how they are independently of our perspectives. The example of a table illustrates the issue: its color varies under different lighting, its shape appears differently from various angles, and its texture feels smooth or rough depending on pressure and motion. From this, Russell concludes that what is directly present in experience are shifting sense-data, not stable physical properties.
From Appearances to Doubt
This variability raises doubts about whether the table, as common sense conceives it (a single, stable object with definite color, shape, and texture), corresponds to anything in reality. Russell uses this to formulate a skeptical challenge: if our perceptions conflict, which, if any, reveal the table “as it really is”?
He then distinguishes between:
- Immediate data (the specific patch of brown, the apparent rectangular shape from a given vantage point).
- Inferred objects (the table as an enduring, three‑dimensional physical object).
The problem of matter arises from the gap between these two.
The Hypothesis of Matter
Russell considers several possible responses:
| Position | Core Idea about Matter |
|---|---|
| Naive realism | Perceived properties (color, shape) simply belong to the object as they appear. |
| Skepticism | We cannot know whether any external object corresponds to our sense-data. |
| Idealism | So‑called material objects are collections of ideas or perceptions; nothing exists unperceived. |
| Critical realism (Russell’s framework) | Matter exists independently but is only indirectly known through sense-data. |
In The Problems of Philosophy, Russell argues that postulating matter—physical objects causing and correlating with our sense-data—offers a simple and coherent explanation of perceptual regularities. However, he concedes that this hypothesis cannot be demonstrated with absolute certainty; it is instead supported as the best available explanation of our experiences.
This discussion sets up the later examination of how, if matter exists, we can have knowledge of it, given that what we directly apprehend are only appearances.
6. Sense-data, Perception, and Idealism
Sense-data and Direct Awareness
Russell uses the term sense-data for the immediate objects of awareness in perception: colored patches, sounds, smells, tactile sensations, and the like. When looking at the table, one is directly aware of a particular visual field, not of the three‑dimensional table as such. Sense-data are:
- Private to the perceiver;
- Depend on conditions such as lighting, position, and the state of the sense organs;
- Known with a high degree of certainty, since doubting them would involve doubting what is immediately given.
On this basis, Russell adopts a version of representative realism: physical objects are not identical with sense-data, but are somehow related to or inferred from them.
Perceptual Relativity and Idealist Arguments
Idealist philosophers, such as Berkeley and later British Idealists, used the relativity of perception to argue that so‑called material objects are “nothing but” complexes of perceptions or ideas. They reasoned that:
- If all we ever experience are sense-data, and these vary with perceivers and conditions, then we have no basis for positing an extra, non‑mental substrate behind them.
- Talk of unperceived matter is meaningless or unjustified; to be is to be perceived (esse est percipi).
Russell carefully reconstructs these arguments, highlighting the appeal of the claim that reality cannot transcend what is in principle experienceable.
Russell’s Response to Idealism
In The Problems of Philosophy, Russell accepts several premises of the idealist critique—especially that we have no direct access to matter—but rejects the conclusion that reality is fundamentally mental. His counter‑strategy involves:
- Separating epistemic dependence (our knowledge of the world depends on sense-data) from ontological dependence (whether the world itself depends on being perceived).
- Arguing that positing an external world of physical objects is a hypothesis that best explains the coherence, intersubjective agreement, and regularity of sense-data across different observers.
Some interpreters classify this as a form of critical realism: perception provides only mediated awareness of the external world, yet that world is not reduced to, nor constituted by, mental items. Subsequent philosophers have debated whether Russell’s reliance on sense-data ultimately supports realism, phenomenalism, or some hybrid position.
7. Acquaintance, Description, and the Objects of Knowledge
A central contribution of The Problems of Philosophy is Russell’s distinction between knowledge by acquaintance and knowledge by description, which structures his account of how we know different kinds of objects.
Knowledge by Acquaintance
Acquaintance is direct, non‑inferential awareness of an entity. Russell claims that we are acquainted with:
- Our own sense-data (the immediately perceived color, sound, etc.);
- Certain universals (such as similarity or spatial relations) given in experience;
- Possibly the self as subject of experience.
Knowledge by acquaintance does not involve identifying the object under a description; it is simply being presented with it. For example, seeing a particular patch of red involves acquaintance with that sense-datum.
Knowledge by Description
By contrast, knowledge by description is knowledge of something as “the so‑and‑so,” where “the so‑and‑so” is a definite description that is, in principle, uniquely satisfied. Typical cases include:
- “The present King of France” (Russell’s famous example in other writings);
- “The author of Waverley”;
- “The table in my room.”
In these cases, we may not be directly acquainted with the object, but we know that there is (or was) an entity fitting the description. Russell holds that:
Every proposition which we can understand must be composed wholly of constituents with which we are acquainted.
Thus, even when we know an object only by description, the terms of the description must ultimately be grounded in acquaintance (with sense-data, universals, or other familiar items).
Epistemic Implications
This framework allows Russell to explain:
- How we can have knowledge of physical objects (e.g., “the cause of these sense-data”) despite only being acquainted with sense-data;
- How we can refer to distant or historical entities (e.g., “the first man to climb Everest”) without any direct contact with them.
Critics have questioned whether any knowledge is genuinely free of descriptive content, and whether acquaintance can be as conceptually “pure” as Russell suggests. Nonetheless, the distinction has played a major role in discussions of reference, perception, and the structure of justification.
8. Induction, General Principles, and A Priori Knowledge
The Problem of Induction
In the chapter “On Induction,” Russell revisits the classical problem associated with Hume: how can we justify inferences from observed cases to unobserved ones? For instance, from many observed instances of bread nourishing, we infer that bread will nourish in the future. Russell notes that:
- This inference is not deductively valid; the premises could be true while the conclusion is false.
- Justifying induction by appeal to its past success would itself be an inductive argument, risking circularity.
He concludes that the principle that the future will resemble the past—or that unobserved cases will conform to observed regularities—cannot be proved either deductively or inductively.
Nonetheless, Russell maintains that inductive principles function as basic postulates of our reasoning and scientific practice. They might be regarded as natural beliefs we are practically compelled to adopt, even though their ultimate justification remains problematic.
General Principles and A Priori Knowledge
Russell distinguishes between particular empirical facts and general principles, which may be:
- Empirical generalizations, such as “All men are mortal,” based on observation and induction.
- A priori principles, especially in logic and mathematics, whose justification does not rest on experience.
In “On Our Knowledge of General Principles” and “How A Priori Knowledge Is Possible,” Russell argues that:
- Certain logical principles (e.g., the law of non‑contradiction) and some principles of inference are known a priori.
- Such knowledge concerns relations among universals (for example, the relation of implication between propositions), rather than contingent features of the physical world.
He contrasts this with more empiricist accounts, which interpret logical necessity as a matter of psychological habit or linguistic convention. Russell instead treats a priori truths as about an objective realm of abstract entities, accessed through intellectual insight rather than sensory experience.
Subsequent philosophers have debated the extent and nature of a priori knowledge, with some endorsing Russell’s realist view of logical relations and others proposing conventionalist, pragmatic, or deflationary accounts.
9. Universals, Propositions, and the World of Abstracta
Realism about Universals
In the chapters “The World of Universals” and “On Our Knowledge of Universals,” Russell defends realism about universals: entities such as qualities (whiteness, hardness), relations (before, greater than), and numbers that can be shared by many particulars. According to Russell:
- When we say “this is white” and “that is white,” we are ascribing the same universal whiteness to different particulars.
- General truths, like “all men are mortal,” are about relations among universals (humanity, mortality) as instantiated in particulars.
He contrasts his view with:
| View | Core Claim about Universals |
|---|---|
| Nominalism | Only particular things exist; universals are merely names or words. |
| Conceptualism | Universals exist only as mental concepts. |
| Realism (Russell) | Universals exist independently of particular instances and of our thinking. |
Russell argues that universals are indispensable to explaining meaning, similarity, laws of nature, and the content of general propositions.
Propositions as Structured Complexes
Russell also develops an ontology of propositions—the contents of judgments and beliefs. A proposition is a structured complex whose components include:
- Particulars (e.g., Socrates, this table);
- Universals (e.g., wisdom, on‑top‑of);
- A logical form that combines these constituents.
On this view, the proposition “Socrates is wise” consists of the particular Socrates, the universal wisdom, and the relational form of predication. Propositions are the primary bearers of truth and falsehood and correspond to facts in the world.
This account underpins Russell’s correspondence theory of truth (developed more fully in the chapter on truth and falsehood), where a true proposition is one whose structure matches a real fact composed of the same constituents in the same arrangement.
Abstracta and Knowledge
Russell holds that we are sometimes acquainted with universals directly (for example, with similarity when we compare two colors) and that many a priori truths involve only universals. Thus, his epistemology requires a realm of abstracta accessible to the mind but not located in space and time.
Critics have objected that this ontology may be metaphysically extravagant or obscure, while defenders emphasize its explanatory power for logic, mathematics, and semantics. Within The Problems of Philosophy, it functions as the backdrop for Russell’s treatment of truth, judgment, and a priori knowledge.
10. Truth, Falsehood, and the Nature of Judgment
Correspondence Theory of Truth
In the chapter “Truth and Falsehood,” Russell articulates a correspondence theory of truth. According to this view:
- A proposition is true if there is a fact corresponding to it—an arrangement of objects and universals in the world matching the structure of the proposition.
- A proposition is false if there is no such fact.
For example, the proposition “this table is brown” is true if and only if there exists a fact consisting of the particular table and the universal brownness standing in the appropriate relation.
Russell distinguishes between:
| Item | Role |
|---|---|
| Belief/Judgment (mental act) | The subjective act of a person taking a proposition to be true. |
| Proposition (content) | The object of belief, capable of being true or false. |
| Fact (state of affairs) | What makes a true proposition true. |
This tripartite structure allows an analysis of error: we can judge falsely when the proposition we judge does not correspond to any fact.
The Nature of Judgment
Russell’s account of judgment treats it as a relation between a subject (the knower) and a proposition. The act of judging does not create the proposition; rather, it relates the mind to a proposition that can exist independently of being thought.
This raises a classical problem: if error is possible, how can we be genuinely related to non‑existent facts? Russell’s solution is that in a false judgment, the mind is still related to a proposition, but the proposition lacks a corresponding fact in reality. Thus, judgment is always to propositions, not to facts directly.
He also maintains that the constituents of a proposition—particulars and universals—must be things with which we are acquainted, at least in principle. This supports his earlier epistemological restrictions on what we can meaningfully think or assert.
Later philosophers have debated:
- Whether facts, so understood, are necessary in the ontology;
- How to accommodate negative truths (“the cat is not on the mat”) and modal truths within a correspondence framework;
- Whether propositions are best conceived as structured entities, sets of possible worlds, or in other ways.
Within The Problems of Philosophy, Russell’s aim is primarily to clarify the conditions under which beliefs qualify as knowledge or error, rather than to offer a fully elaborated metaphysics of facts.
11. Knowledge, Error, and Probable Opinion
In “Knowledge, Error, and Probable Opinion,” Russell investigates how knowledge differs from mere opinion and error, and how probability permeates much of what we commonly call knowledge.
Knowledge vs. Error
Russell uses his correspondence view to characterize:
- Knowledge as true belief (or true judgment) that is supported by adequate evidence or justification.
- Error as belief whose propositional content fails to correspond to any fact.
He emphasizes that in cases of error, the mind may still be acquainted with the constituents of the proposition; what goes wrong is the way these constituents are combined. Thus, error is compatible with acquaintance and does not imply complete ignorance of the elements involved.
Probable Opinion
Much of our everyday and scientific belief, Russell contends, falls short of certainty. He introduces probable opinion to capture beliefs that are:
- Not conclusively justified;
- Yet supported by evidence to a greater or lesser degree.
Such opinions are formed especially through inductive reasoning, testimonial evidence, and inference to the best explanation. Russell suggests that we are often rationally required to act on probable opinions, even while recognizing that they may turn out to be mistaken.
He thereby sketches a continuum:
| Type of Attitude | Truth-Value | Evidential Status |
|---|---|---|
| Knowledge | True | Strong, adequate justification |
| Probable opinion | True or false | Some but incomplete justification |
| Error | False | Typically appears justified to the agent but lacks adequate grounding |
Graded Justification and Skepticism
Russell does not attempt to give a formal probability calculus in this work, but he maintains that rational belief admits of degrees. He also acknowledges that skepticism about many specific beliefs is difficult to refute conclusively; nonetheless, he argues that complete suspension of judgment is rarely practical.
Later epistemologists have reconstructed Russell’s remarks in terms of fallibilism (the idea that knowledge is compatible with the possibility of error) and have debated whether his understanding of knowledge as justified true belief anticipates or differs from later analyses that focus on reliability, safety, or the avoidance of Gettier‑style counterexamples.
12. Philosophical Method and Logical Analysis
Although The Problems of Philosophy is not a methodological treatise, it exemplifies and occasionally comments on a characteristic philosophical method that became influential in analytic philosophy.
Analysis of Concepts and Propositions
Russell repeatedly employs logical analysis: the attempt to break down complex expressions or beliefs into simpler components, clarifying their structure and ontological commitments. This method appears in:
- The analysis of perception into sense-data and inferred physical objects;
- The separation of acquaintance from description in reference;
- The decomposition of propositions into particulars, universals, and logical form.
The guiding idea is that many philosophical puzzles arise from surface grammatical forms that obscure the underlying logical structure. By revealing this structure, Russell aims to dissolve confusions and to determine what kinds of entities we must accept in our ontology.
Use of Ordinary Language and Thought Experiments
While later analytic philosophers often emphasize ordinary language, Russell oscillates between everyday examples (the table, the cat, ordinary spatial relations) and semi‑formal talk of propositions and universals. He uses simple thought experiments—such as varying perceptual conditions—to elicit intuitions about appearance, reality, and knowledge.
Methodological Themes
Several methodological theses are implicit:
- Fallibilism: even fundamental beliefs, such as the existence of the external world, are revisable; philosophy should clarify degrees of justification rather than promise absolute certainty.
- Independence of Logic from Psychology: logical relations are not reducible to mental habits; philosophy must distinguish normative principles of reasoning from the psychological processes by which we in fact think.
- Priority of Epistemology to Metaphysics (within the book): questions about what there is are approached through questions about what we can know and how.
Some interpreters see The Problems of Philosophy as an early exemplar of analytic philosophy’s focus on language, logic, and argument, even though Russell’s use of formal symbolism is minimal in this work. Others emphasize continuities with traditional epistemology, noting that his method remains closely tied to reflection on experience and common‑sense beliefs.
13. Famous Passages and Illustrative Examples
Russell’s exposition is punctuated by vivid examples and passages that have become standard teaching tools in introductory philosophy.
The Table and the Distinction between Appearance and Reality
The opening pages use a familiar table as a case study:
“It is evident that the real table, if there is one, is not the same as what we immediately experience by sight or touch or hearing.”
— Bertrand Russell, The Problems of Philosophy, ch. I
By varying lighting, position, and tactile inspection, Russell shows that no single set of sensible qualities can be identified with the “real” table. This example introduces sense-data, appearance vs. reality, and the problem of matter.
Sense-data and the Uncertainty of the Outer World
In discussing the existence of matter, Russell notes:
“…although the existence of matter is not logically necessary, yet it is rational to believe it.”
— The Problems of Philosophy, ch. II
He argues that the hypothesis of an external world of physical objects best explains the order and regularity of sense-data, even if alternative hypotheses (such as dream or hallucination scenarios) cannot be conclusively refuted.
Acquaintance and Description
Russell’s distinction appears in the oft‑cited discussion of knowing “the author of Waverley” versus knowing “Scott.” We may know that there is some person who wrote Waverley (by description) without being acquainted with Scott himself. This example illustrates how we can think and talk about objects beyond our direct experience.
The Value of Philosophy
Although strictly belonging to the closing chapter, a widely quoted passage captures Russell’s view of philosophy’s significance:
“The man who has no tincture of philosophy goes through life imprisoned in the prejudices derived from common sense and from the habitual beliefs of his age…”
— The Problems of Philosophy, ch. XV
Here Russell emphasizes the role of philosophy in widening our conception of what is possible and freeing us from unexamined assumptions.
These examples and passages have been frequently excerpted in anthologies and textbooks, serving both as introductions to Russell’s own views and as starting points for broader discussions in epistemology and metaphysics.
14. Key Concepts and Technical Vocabulary
The Problems of Philosophy introduces a compact but influential set of technical terms. Some central ones include:
| Term | Brief Explanation (in Russell’s Usage) |
|---|---|
| Appearance | How things seem in perception, constituted by sense-data that vary with viewpoint and conditions. |
| Reality | The mind‑independent world, including physical objects and facts, as it is in itself. |
| Sense-data | Immediate objects of sensation (colors, sounds, etc.) directly given to consciousness, contrasted with inferred physical things. |
| Matter / Physical object | An enduring, external entity posited to explain the patterns and causes of sense-data. |
| Idealism | The view that reality is fundamentally mental, or that so‑called material objects are dependent on being perceived. |
| Knowledge by acquaintance | Direct, non‑inferential awareness of an object (sense-data, some universals, possibly the self). |
| Knowledge by description | Knowledge of an object via a description that uniquely picks it out, grounded in acquaintance with the terms of the description. |
| Universal | An abstract entity (quality, relation, or sometimes class) that can be instantiated by many particulars and figures in general truths. |
| Particular | A specific, individual entity (this table, that patch of color) that instantiates universals. |
| A priori knowledge | Knowledge justified independently of particular sensory experiences, typically of logical or mathematical truths and some general principles. |
| Induction | Non‑deductive reasoning from observed instances to unobserved cases or general laws. |
| Intuitive knowledge | Immediate, non‑inferential knowledge, including some self‑knowledge, memory of one’s own experiences, and insight into simple logical relations. |
| Proposition | The content of a belief or judgment, a structured complex of particulars, universals, and logical form, capable of being true or false. |
| Fact | A state of affairs in the world that makes a true proposition true; consists of objects and universals combined in a certain way. |
| Correspondence theory of truth | The theory that a proposition is true if it corresponds to a fact and false if it does not. |
| Critical realism | A position that affirms a mind‑independent reality but holds that our knowledge of it is indirect, mediated by sense-data and inference. |
Later philosophers have sometimes modified or replaced Russell’s terminology, but many of these concepts remain standard reference points in analytic epistemology and metaphysics.
15. Legacy and Historical Significance
The Problems of Philosophy has had a lasting impact both as a pedagogical text and as a landmark in the development of analytic philosophy.
Role in Analytic Philosophy
The book helped to establish several themes that became central to analytic thought:
- The use of logical analysis to clarify traditional metaphysical and epistemological problems.
- A focus on language, propositions, and truth as key to understanding knowledge and reality.
- A willingness to posit abstract entities (universals, propositions, facts) when required by explanatory considerations.
It also contributed to the decline of British Idealism by offering a clear alternative grounded in realism about both the external world and logical structure.
Educational Influence
Because of its relative brevity and clarity, the book quickly became a standard introduction in English‑speaking universities. Generations of students first encountered debates about:
- The appearance–reality distinction;
- The external world and skepticism;
- A priori knowledge and universals;
through Russell’s formulations. Many later philosophers report that their initial interest in analytic philosophy was sparked by reading this text.
Critical Reception and Ongoing Debates
Over time, the work has attracted both admiration and criticism:
- Sense-data theory has been widely challenged as phenomenologically artificial and ontologically problematic; many contemporary philosophers favor direct realist or disjunctivist accounts of perception.
- Russell’s realism about universals and facts has been contested by nominalists, conceptualists, and deflationary theorists of truth and propositions.
- The sharp divide between acquaintance and description has been questioned by philosophers who argue that all cognition is conceptually mediated.
Despite these challenges, the book is frequently cited in discussions of foundational issues in epistemology and metaphysics, both as a source of enduring distinctions (such as acquaintance/description) and as a foil for more recent views.
Place in Russell’s Oeuvre
Within Russell’s own corpus, The Problems of Philosophy is often read as a concise expression of his early mature position, bridging his technical work in logic with his more general writings on knowledge and reality. Later shifts in his views on perception and the nature of propositions have led scholars to trace continuities and discontinuities between this book and his subsequent philosophical development.
As a result, The Problems of Philosophy occupies a dual status: a historical document of the early analytic movement and an ongoing point of reference in contemporary philosophical debates.
Study Guide
beginnerThe book is written as an accessible introduction for students and non‑specialists, with minimal technical notation. However, it assumes patience with abstract argument, and some sections on universals, propositions, and a priori knowledge can feel like early‑intermediate analytic metaphysics and epistemology.
Appearance vs. Reality
The distinction between how things seem to us in perception—given as shifting, perspective‑dependent sense-data—and how they are in themselves as mind‑independent objects and facts.
Sense-data
The immediate objects of sensation (patches of color, sounds, tactile feelings, etc.) that we are directly aware of in perception, contrasted with external physical objects we infer from them.
Matter / Physical Objects
Hypothesized external, enduring entities that cause and explain regularities in our sense-data; they are not directly given but postulated to make sense of experience.
Idealism vs. Critical Realism
Idealism claims reality is fundamentally mental or dependent on being perceived; Russell’s critical realism holds that a mind‑independent world exists, but our knowledge of it is indirect, fallible, and mediated by sense-data and inference.
Knowledge by Acquaintance and Knowledge by Description
Knowledge by acquaintance is direct, non‑inferential awareness of objects (sense-data, some universals, possibly the self); knowledge by description is knowledge of objects only through descriptions that pick them out, grounded in acquaintance with the terms of the description.
A priori Knowledge and Universals
A priori knowledge is justified independently of particular sensory experiences and, for Russell, typically concerns universals and their relations—logical, mathematical, and some general principles—rather than contingent empirical facts.
Propositions, Facts, and the Correspondence Theory of Truth
Propositions are structured contents of judgment involving particulars and universals; facts are states of affairs in which such constituents are combined; truth consists in a proposition’s structural correspondence to a fact, and falsehood in the lack of such a fact.
Induction, Probable Opinion, and the Limits of Knowledge
Induction is reasoning from observed to unobserved cases; for Russell it cannot be ultimately justified, yet is practically indispensable. Many beliefs thus count as probable opinions—supported by evidence but short of certainty—illustrating the fallible, graded nature of much of our knowledge.
Does Russell successfully show that belief in an external world of matter is more reasonable than skepticism or idealism, given that we only ever experience sense-data?
How does Russell’s distinction between knowledge by acquaintance and knowledge by description help explain how we can think about and refer to objects we have never directly perceived?
What is the problem of induction as Russell understands it, and why does he think it cannot be justified by either deduction or induction without circularity?
Why does Russell think that universals are indispensable for understanding meaning, similarity, and general truths? Could a consistent nominalist account preserve these phenomena without committing to universals?
In what sense is Russell’s theory of truth a ‘correspondence’ theory, and how does his tripartite distinction between beliefs, propositions, and facts help make sense of error?
How does Russell argue that some knowledge—especially in logic and mathematics—is a priori, and what role do universals play in making sense of this?
According to Russell, in what ways does philosophy have value even if it cannot provide definitive answers to many of its questions?
To what extent does Russell’s reliance on sense-data as the immediate objects of awareness create problems for his realism about the external world?
How to Cite This Entry
Use these citation formats to reference this work entry in your academic work. Click the copy button to copy the citation to your clipboard.
Philopedia. (2025). the-problems-of-philosophy. Philopedia. https://philopedia.com/works/the-problems-of-philosophy/
"the-problems-of-philosophy." Philopedia, 2025, https://philopedia.com/works/the-problems-of-philosophy/.
Philopedia. "the-problems-of-philosophy." Philopedia. Accessed December 11, 2025. https://philopedia.com/works/the-problems-of-philosophy/.
@online{philopedia_the_problems_of_philosophy,
title = {the-problems-of-philosophy},
author = {Philopedia},
year = {2025},
url = {https://philopedia.com/works/the-problems-of-philosophy/},
urldate = {December 11, 2025}
}