Editor's Introduction.- I. Logic as a Theory of Science.- II. Propositions and Sentences.- III. Ideas in Themselves.- IV. The Reduction of Sentences.- V. Judgment and Knowledge.- VI. Intuition and Concept.- VII. The Notion of Variation.- VIII. Analytic and Synthetic Propositions.- IX. Consistency and Derivability.- X. Degree of Validity and Probability.- XI. The Objective Hierarchy of Propositions.- XII. Set and Continuum.- XIII. Infinite Sets.- XIV. Natural Numbers.- XV. Conclusion.- A A Selection from the Wissenschaftslehre (Sulzbach 1837, Leipzig 1914-31) [`+A' (`-A') means including (excluding) the Anmerkung(en)]: Volume One.- 1. What the Author Understands by Theory of Science.- 2. Justification of this Concept and Its Designation.- 15. Plan for Carrying out Logic According to the Author's Understanding.- One / Theory of Fundamental Truths.- One / On the Existence of Truths in Themselves.- 19. What the Author Understands by a Proposition in Itself (+A).- 21. That Others Have Already Made Use of this Concept.- 24. Various Meanings of the Words: True und Truth (-A).- 25. What the Author Understands by Truths in Themselves.- 26. Differentiation of this Concept from Some that Are Related to It.- 30. The Meaning of the Claim that there Are Truths in Themselves.- 31. Proof that there Is At Least One Truth in Itself (+A).- 32. Proof that there Are a Number of Truths, Indeed an Infinite Number (+A).- Two / On the Possibility of Knowing the Truth.- 34. What the Author Understands by a Judgment (-A).- 35. Examination of Other Definitions of this Concept (Subsection 5).- 36. What Would the Author Understand by a Cognition?.- 40. How It Can Be Proved that We Know At Least One Truth.- 41. How It Can Be Proved that We Are Capable of Knowing an Indefinitely Large Number of Truths (+A).- Two / Theory of Elements 46. Purpose, Content and Sections of this Part.- One / On Ideas in Themselves.- 48. What the Author Understands by Ideas in Themselves and by Ideas Possessed.- 49. Differentiation of the Concept of an Idea in Itself from Some Related Concepts.- 50. Justification of this Concept.- 51. That this Concept Is Already Encountered in Others (Subsection 1).- 54. Ideas in Themselves Have No Existence.- 55. Ideas in Themselves Are neither True nor False (-A).- 56. Parts and Content of an Idea in Itself (-A).- 58. Closer Examination of the Most Notable Ways in which Ideas Are Compounded.- 60. Concrete and Abstract Ideas (-A).- 61. There Must also Be Simple Ideas.- 63. Are the Parts of an Idea the Same as the Ideas of the Parts of Its Object?.- 64. Are the Parts of an Idea the Same as the Ideas of Its Object's Properties? (-A).- 66. The Concept of the Extension of an Idea (-A).- 67. There Are also Objectless Ideas (+A).- 68. There Are also Ideas that Have Only a Finite Set of Objects, and Singular Ideas as Well (-A).- 70. Real and Imaginary Ideas (+A).- 71. Two Consequences (+A).- 72. What the Author Understands by Intuitions (-A).- 73. What Is It that the Author Calls Concepts and Mixed Ideas?.- 75. Some Remarks on the Difference between the Ways in which Intuitions and Concepts Are Designated.- 78. Differences among Concepts with Respect to Content and Extension (+A 1-2, to p. 356,1. 12, of the German text).- 80. Ideas of Qualities and Relations (-A).- 84. Concepts of Sets and Sums (-A).- 86. Concepts of Unity, Plurality and Universality.- 87. Concepts of Quantity, Both Finite and Infinite (-A).- 90. Symbolic Ideas (-A).- 91. There Are No Two Completely Identical Ideas. Similar Ideas (+ A 1-2).- 92. Relations among Ideas with Respect to Their Content (-A).- 93. Relations among Ideas with Respect to Their Breadth (-A).- 94. Relations among Ideas with Respect to Their Objects (-A).- 95. Special Kinds of Compatibility: (a) Inclusion (+A).- 96. (b) The Relationship of Mutual Inclusion, or Equivalence (-A).- 97. (c) The Relationship of Subordination (-A).- 98. (d) The Relationship of Intersection or Concatenation (-A).- 102. No Finite Set of Standards Is Sufficient to Measure the Breadths of All Ideas.- 103. Particular Kinds of Incompatibility among Ideas (-A).- 108. How the Relationships Discussed in 93ff Can Be Extended to Objectless Ideas as Well (+A).- 120. On the Rule that Content and Extension Stand in an Inverse Relationship.- Volume Two.- Two / On Propositions in Themselves.- 122. No Proposition in Itself Is an Existent.- 123. Every Proposition Necessarily Contains Several Ideas. Its Content (-A).- 124. Every Proposition Is Capable of Being Considered as a Component of Another Proposition, or Even of a Mere Idea.- 125. Every Proposition Is either True Or False and True or False in All Times and at All Places.- 126. Three Components that Are Undeniably Found in a Large Number of Propositions.- 127. Which Components Does the Author Assume for All Propositions?.- 130. The Extension of a Proposition Is Always the Same as the Extension of Its Base (-A).- 133. Conceptual Propositions and Empirical Propositions (+A).- 137. Various Propositions about Ideas: (a) Assertions of the Denotative Character of an Idea.- 138. (b) Denials of the Denotative Character of an Idea (-A).- 139. (c) Further Propositions that Define the Extension of an Idea More Closely.- 146. Objectless and Denotative, Singular and General Propositions.- 147. The Concept of the Validity of a Proposition.- 148. Analytic and Synthetic Propositions (+A).- 154. Compatible and Incompatible Propositions (-A).- 155. Special Types of Compatibility: (a) The Relation of Derivability (+A).- 156. (b) The Relation of Equivalence (+A).- 157. (c) The Relationship of Subordination.- 158. (d) The Relationship of Concatenation.- 159. Special Types of Incompatibility (-A).- 160. Relations among Propositions Resulting from Consideration of How Many True or False Propositions there Are in a Set (+A).- 161. The Relationship of Comparative Validity or the Probability of a Proposition with Respect to Other Propositions (+A2 from p. 189, 1. 10, of the German text).- 162. The Relation of Ground and Consequence.- 167. Propositions which Assert a Relation of Probability.- 168. Propositions which Assert a Relation of Ground and Consequence (Subsection 3).- 174. Propositions of the Form: n A are B (+A).- 179. Propositions with If and Then (+A).- 182. Propositions Containing the Concept of Necessity, Possibility or Contingency (-A).- Three / On True Propositions.- 198. The Concept of a Ground-Consequence Relationship between Truths (-A).- 199. Can the Inference Rule also Be Counted among the Partial Grounds of a Conclusion? (-A).- 200. Is the Relation of Ground and Consequence Subordinate to that of Derivability?.- 203. Only Truths Are Related as Ground and Consequence (Subsection 1).- 204. Can Something Be Ground and Consequence of Itself? (-A).- 205. Are Ground and Consequence in Each Case only a Single Truth or a Set of Several Truths?.- 206. Can One Ground Have a Variety of Consequences or One Consequence a Variety of Grounds?.- 207. Can One Regard the Consequence of a Part as the Consequence of the Whole?.- 209. Can a Truth or a Whole Set of Truths Be both Ground and Consequence in One and the Same Relation? (-A).- 210. Can a Set of Several Grounds Be Regarded as the Ground of a Set of Several Consequences?.- 211. Is there a Rank Order among the Parts of the Ground or of the Consequence?.- 213. Can the Consequence of the Consequence Be Considered a Consequence of the Ground? (-A).- 214. Can Every Truth Be Regarded not only as Ground but also as Consequence of Others? (-A).- 215. Is there More than One Basic Truth? (+A).- 216. Does the Process of Mounting up from Consequences to Its Grounds Have to Come to an End for Every Given Truth?.- 217. What the Author Understands by Subsidiary Truths.- 218. No Truth Can Be a Subsidiary Truth of Itself.- 220. What Kind of Pictorial Representation Can Be Given for the Relationship that Prevails between Truths with Respect to Ground and Consequence?.- 221. Some Criteria for Determining whether Certain Truths Have the Relationship of Dependence (+A).- Four / On Inferences.- 223. Content and Purpose of this Chapter (+A).- 224. Some Rules by which Conclusions to Given Premises Can Be Sought out.- 243. Continuation [Assertions about Numbers].- Volume Three.- Three / Theory of Knowledge.- One / On Ideas.- 270. Concept of an Idea in the Subjective Sense (-A).- 271. There Is an Idea in Itself Attached to Every Subjective Idea (+A).- 272. Every Subjective Idea Is Something Real, but only as an Attribute of a Substance.- 285. Naming Our Ideas (Subsections 1-2).- Two / On Judgments.- 290. The Concept of a Judgment.- 291. Some Properties that Belong to All Judgments (-A).- 292. What We Call a Single Judgment, and when We Say of Several Judgments that They Are Like or Unlike.- 294. Classifications of Judgments that Arise from Classifications of Propositions with the Same Names.- 298. Does Every Judgment Leave a Trace of Itself behind after It Has Passed away?.- 300. Mediation of a Judgment by Other Judgments (-A).- 303. How We Do Arrive at Our Most General Empirical Judgments and how We Can Arrive at Them (-A).- 306. Survey of the Most Noteworthy Activities and States of Our Mind that Concern the Business of Making Judgments (-A).- Three / The Relationship of our Judgments to the Truth.- 307. More Precise Definition of the Concepts: Knowledge, Ignorance and Error (-A).- 309. What Is the Basis of the Possibility of Error and what Circumstances Promote Our Errors' Occurrence?.- 314. Are there Definite Limits to Our Capacity for Knowledge? (+A).- Volume Four.- Five / Theory of Science Proper.- One / General Theory.- 395. The Supreme Principle of All Theory of Science (-A).- 401. A Proper Scholarly Treatise Must also Indicate the Objective Connection between Truths, as far as Possible.- Four / On the Propositions which should Occur in a Scholarly Treatise.- 525. Explaining a Truth's Objective Ground (-A).- 530. Proofs by Reduction to Absurdity (Subsection 1).- 557. How to Prove a Statement Specifying the Composition of an Idea.- 558. How the Proof that a Definition of a Given Proposition Is Correct Must Be Carried out (-A).- B Excerpts from Bolzano's Correspondence.- Letter to J. E. Seidel, 26 January 1833 (Manuscript in Krajske muzeum v Ceskych Bud?jovicich; transcription by Jan Berg).- Letter to M. J. Fesl, 8 February 1834 (Manuscript in Literarni ar chiv Pamatniku narodniho pisemnictvi v Praze; published in Wissenschaft und Religion im Vormarz. Der Briefwechsel Bernard Bolzanos mit Michael Josef Fesl (ed. by E. Winter and W. Zeil), Berlin 1965, p. 58,1. 4 - 1. 3 f.b.).- Letter to F. Exner, 22 November 1834 (Manuscript in OEsterreichische Nationalbibliothek Wien; published in Der Briefwechsel B. Bolzano's mit F. Exner (ed. by E. Winter), Bernard Bolzano's Schriften, vol. 4, Prague 1935, p. 62,1. 32 - p. 67, 1. 38).- Letter to J. P. Romang, 1 May 1847 (Manuscript in the same archive as Letter to M. J. Fesl (above); published in Philosophisches Jahrbuch der Goerresgesellschaft, vol. 51, Fulda 1938, p. 50,1. 5f.b. - p. 53, 1. 16).- Letter to R. Zimmermann, 9 March 1848 (Manuscript in the same archive as Letter to M. J. Fesl (above); transcription by Jan Berg).- Letter to F. P?ihonsky, 10 March 1848 (Manuscript in the same archive as Letter to M. J. Fesl (above); published in E. Winter: Der Boehmische Vormarz in Brief en B. Bolzanos an F. P?ihonski, Berlin 1956, p. 285,1. 1 - 1. 16).- A. Works by Bolzano.- 1. Works on Logic, Epistemology and Methodology of Science.- 2. Works on Mathematics.- B. Works on Bolzano.- 1. General Works.- 2. Biographies.- 3. Logic.- 4. Mathematics.- 5. Metaphysics.- 6. Theology.- 7. Social Philosophy.- 8. Aesthetics.- Name Index.