Key Concepts

Argument Explanation
Tabula Rasa Locke argued that the human mind is a "tabula rasa" or blank slate at birth, and that all knowledge is derived from experience. This challenged the prevailing view that human beings are born with innate ideas.
Empiricism Locke was a proponent of empiricism, which holds that knowledge comes from sensory experience rather than pure reason or innate ideas. He believed that the mind acquires knowledge through the senses and the reflection on our experiences.
Simple and Complex Ideas Locke distinguished between simple ideas, which come directly from sensory experience (such as colors, sounds, and tastes), and complex ideas, which are formed by combining simple ideas (such as the idea of a horse or a triangle).
Primary and Secondary Qualities Locke further divided ideas into primary qualities, which exist objectively in the world (such as shape, motion, and number), and secondary qualities, which are subjective perceptions (such as color, taste, and smell).
Personal Identity Locke explored the concept of personal identity, arguing that it is not based on substance (the material body) but on consciousness and the continuity of memory over time.
Theory of Knowledge Locke proposed a theory of knowledge that distinguished between intuitive knowledge (immediate and self-evident truths), demonstrative knowledge (derived from intuitive knowledge through reasoning), and sensitive knowledge (based on sensory experience).

Quotes

Chapter Quote
Book I, Chapter I "The mind is like a blank slate [tabula rasa] upon which experience writes."
Book II, Chapter I "Our observation, employed either about external sensible objects or about the internal operations of our minds perceived and reflected on by ourselves, is that which supplies our understandings with all the material of thinking."
Book II, Chapter XXVII "Personal identity depends on consciousness, not on substance."
Book IV, Chapter XVI "The assurance of knowledge is not from innate ideas, but from clear and distinct ideas."
Book IV, Chapter XIX "Faith is nothing but a firm assent of the mind; which if it be regulated, as is our duty, cannot be afforded to anything but upon good reason."

Contents

Book Chapter Summary
Book I: Innate Ideas Chapter I: Introduction Explains the purpose of the essay, namely to inquire into the origin, certainty, and extent of human knowledge.
Chapter II: No Innate Principles in the Mind Argues against the existence of innate ideas and that all knowledge is derived from experience.
Chapter III: No Innate Practical Principles Contends that moral principles are not innate and are also derived from experience and observation.
Chapter IV: Further Considerations Concerning Innate Principles Provides additional arguments to refute innate ideas, emphasizing variability in human understanding.
Chapter V: Some Further Considerations on Our Connate Intellectual Ideas Examines more ideas thought to be innate and discredits them as learned experiences.
Book II: Of Ideas Chapter I: Of Ideas in General and Their Original Defines what ideas are and discusses their origin from sensory experience and reflection.
Chapter II: Assent to Native Propositions Argues against the notion of universally accepted innate ideas and beliefs.
Chapters III - XII Explores particular types of ideas acquired through sensation and reflection, such as simple ideas, complex ideas, and modes.
Chapters XIII - XXXIII Discusses various complex ideas such as substances, relations, and conveys the distinction between primary and secondary qualities.
Book III: Of Words Chapter I: Of Words or Language in General Argues that words signify ideas and discusses the role of language in human understanding.
Chapters II - VII Discusses the imperfections and abuses of language, the use of words in different contexts, and the importance of definitions.
Chapters IX - XI Explores specific problems of language such as the essence of words, their relationship to ideas, and how words are used to represent substances and complex ideas.
Book IV: Of Knowledge and Probability Chapter I: Of Knowledge in General Defines knowledge as the perception of the agreement or disagreement of ideas and introduces the degrees of knowledge: intuitive, demonstrative, and sensitive.
Chapters II - IX Examines different types of knowledge (e.g., of existence, of mathematics, of morality), certainty, and the scope and limits of human understanding.
Chapters X - XXI Focuses on judgment and probability, opinion and assent, faith and reason, and finally concludes with the differences between knowledge and belief.