1. Non-scientific symbols in science

   • Philipp G. Frank

   OriginalPaper 01 January 1955 Pages: 3 - 9

2. Obituary Hans Reichenbach

   • J. Clay

   Announcement 01 January 1955 Pages: 10 - 12

3. An exemplification of “operational methodology”

   • Vittorio Somenzi

   OriginalPaper 01 January 1955 Pages: 15 - 25

4. Le developpement du probleme de l'Unite de la Science dans l'Empirisme Logique

   • Jacques Ruytinx

   OriginalPaper 01 January 1955 Pages: 26 - 41

5. Tautology tessellations

   • D. P. Henry

   OriginalPaper 01 January 1955 Pages: 42 - 47

6. The analysis of counterfactual conditionals

   • Gabriel Nuchelmans

   OriginalPaper 01 January 1955 Pages: 48 - 63

7. Philosophical periodicals

   Announcement 01 January 1955 Pages: 64 - 64

8. Book reviews

   • Emile Sicard

   BookReview 01 January 1955 Pages: 67 - 70

9. Les Activities Mentales en rapport avec les Expressions Symboliques logiques et mathematiques

   • Jean Piaget

   OriginalPaper 01 January 1955 Pages: 73 - 90

10. G. F. C. Griss and his negationless intuitionistic mathematics

    • A. Heyting

    OriginalPaper 01 January 1955 Pages: 91 - 96

11. Quantum mechanics and its models

    • H. J. Groenewold

    OriginalPaper 01 January 1955 Pages: 97 - 103

12. On the application of the concept of precisation

    • Laura Grimm

    OriginalPaper 01 January 1955 Pages: 104 - 120

13. Book reviews

    • W. Manders
    • D. Vuysje

    BookReview 01 January 1955 Pages: 123 - 126

14. Corrigendum

    Announcement 01 January 1955 Pages: 128 - 128

15. Inaugural address

    • P. H. Esser

    Report 01 January 1955 Pages: 133 - 136

16. Some informal information on “information”

    • D. van Dantzig

    OriginalPaper 01 January 1955 Pages: 137 - 144

17. Semantic and signific aspects of modern theories of communication

    • G. Mannoury
    • D. Vuysje

    OriginalPaper 01 January 1955 Pages: 147 - 156

18. What is information?

    • Anatol Rapoport

    OriginalPaper 01 January 1955 Pages: 157 - 173

19. An introduction to scientific information

    • J. L. van Soest

    OriginalPaper 01 January 1955 Pages: 177 - 181

20. Operational aspects of some fundamental concepts of human communication

    • D. M. Mackay

    OriginalPaper 01 January 1955 Pages: 182 - 198

21. On the concepts of endechy and manipulation and their application to information theory

    • J. F. Schouten

    OriginalPaper 01 January 1955 Pages: 199 - 204

22. Une contribution aux theories modernes de communication: machines de Turing et problemes de mot

    • Dov Tamari

    OriginalPaper 01 January 1955 Pages: 205 - 227

23. Introduction

    • J. Droogleever Fortuyn

    EditorialNotes 01 January 1955 Pages: 231 - 232

24. Information in the head

    • Warren S. McCulloch

    OriginalPaper 01 January 1955 Pages: 233 - 247

25. The mathematical biology of physiological excitation

    • George Karreman

    OriginalPaper 01 January 1955 Pages: 248 - 251

26. The information capacity of the human ear and of the cochlear nerve

    • Hl. de Vries

    OriginalPaper 01 January 1955 Pages: 252 - 254

27. Recent mathematical-biological studies on communication

    • George Karreman

    OriginalPaper 01 January 1955 Pages: 255 - 261

28. A contribution of information to sociology

    • J. L. van Soest

    OriginalPaper 01 January 1955 Pages: 265 - 273

29. Foundations of organization

    • B. Poortman

    OriginalPaper 01 January 1955 Pages: 274 - 288

30. The communicative process

    • Surindar Suri

    OriginalPaper 01 January 1955 Pages: 289 - 295

31. Information and content: A semantic analysis

    • Yehoshua Bar-Hillel

    OriginalPaper 01 January 1955 Pages: 299 - 305

32. Logic, cybernetics, and semantics

    • Oliver L. Reiser

    OriginalPaper 01 January 1955 Pages: 306 - 318

33. Transformation of speech into writing and simplification

    • A. J. J. De Witte

    OriginalPaper 01 January 1955 Pages: 321 - 325

34. Concealment of information

    • M. De Vries

    OriginalPaper 01 January 1955 Pages: 326 - 336

35. Final speech

    • P. H. Esser

    Report 01 January 1955 Pages: 339 - 339

36. Criteria of meaning and analysis of usage

    • Ingemund Gullvåg

    OriginalPaper 01 January 1955 Pages: 341 - 361

37. The distinction between modernizing and dissolving aesthetics

    • Campbell Crockett

    OriginalPaper 01 January 1955 Pages: 362 - 371

38. The logical nature of arithmetic

    • Th. Skolem

    OriginalPaper 01 January 1955 Pages: 375 - 384

39. Validity of hypotheses

    • R. Vermeulen

    OriginalPaper 01 January 1955 Pages: 385 - 394

40. L'objet de la Geometrie

    • J. J. W. Berghuys

    OriginalPaper 01 January 1955 Pages: 395 - 407

41. Book reviews

    • E. W. Beth
    • Esser
    • Leo Apostel

    BookReview 01 January 1955 Pages: 411 - 416

42. In memoriam Jacob Clay

    • The Dutch Members of the General Editorial Committee

    Announcement 01 January 1955 Pages: 423 - 427

43. The physicist J. Clay

    • H. F. Jongen

    Announcement 01 January 1955 Pages: 428 - 432

44. Einstein

    • Philipp G. Frank

    Announcement 01 January 1955 Pages: 435 - 437

45. The cultural phenomenon albert Einstein

    • G. Mannoury

    OriginalPaper 01 January 1955 Pages: 438 - 441

46. Albert Einstein, inventor of chronogeometry

    • A. D. Fokker

    OriginalPaper 01 January 1955 Pages: 442 - 445

47. Nieuwentyt's significance for the philosophy of science

    • E. W. Beth

    OriginalPaper 01 January 1955 Pages: 447 - 453

48. Nieuwentijt und der teleologische Gottesbeweis

    • Hans Freudenthal

    OriginalPaper 01 January 1955 Pages: 454 - 464

49. Die Mathematik als ein zugleich Vertrautes und Unbekanntes

    • Paul Bernays

    OriginalPaper 01 January 1955 Pages: 465 - 471

50. Die Syllogistik des Johannes Hospinianus (1515–1575)

    • Karl Dürr

    OriginalPaper 01 January 1955 Pages: 472 - 484