In 1900-01, my Logical Investigations appeared as the result of ten year's worth of efforts for a clarification of the pure idea of logic by a return to the bestowing of sense or the performance of cognition which occurs in the nexus of lived experiences of logical thinking. More accurately speaking, the single investigations of the second volume involved a turning of intuition back toward the logical lived experiences which take place in us whenever we think but which we do not see just then, which we do not have in our noticing view whenever we carry out thought activity in a naturally original manner... The point was to bring this obscurely occuring life of thinking into one's grip by subsequent reflection and to fix it in faithful descriptive concepts. [From the Phenomenological Psychology , Introduction, section 3].

Husserl's most original contribution in the Logical Investigations, arguably, lies in his analysis of intentionality and meaning, relating mind and language to the rest of the world. Beyond the structures of consciousness and language, however, lie basic ontological structures which Husserl analyzed with often novel insight in the Investigations . The theory of universals began in the West with Plato and Aristotle, and dominated much of Medieval philosophy. Husserl sought a renewed theory of universals, or 'ideal species', and at the same time tied 'ideal meanings? into the logical structure of language and thought. Moreover, at work in all his results were his conception and application of part-whole theory, or mereology (as distinct from set theory).

Husserl (1859-1938) was 41 years old when this 1000-page work appeared in 1900-01. With the Logical Investigations Husserl matured into a full-fledged philosopher. The Investigations occupy some 1000 pages in three volumes in the German edition: including the Prolegomena and six Investigations numbered I - VI. The first edition was published in 1900 and 1901. The second edition, with revisions through Investigation V, was published in 1913; the second edition of Investigation VI, with revisions, was published in 1920. There was no English translation of the whole work until that by J. N. Findlay in 1970: 877 pages in two volumes, translating the full second edition.

Those who read the Investigations seriously, as a unified piece of philosophy, confront a basic textual question: by what rights is anything but the Prolegomena an investigation into logic? Why isn't the Logical Investigations an utterly misnamed work? Roughly, the first of the Investigations is a semantics, the second an account of universals, the third a mereology, the fourth a return to semantics, the fifth and sixth a theory of consciousness. The motley lot are prefaced by the Prolegomena, Husserl's famed critique of psychologism. Husserl began the Investigations by announcing logic as the work's dominant theme; the Prolegomena touts logic as "the theory of science" itself. How is that "theme" reprised? The finale of the Investigations is a theory of consciousness. In Investigations VI Husserl developed and expanded the treatment of the mental act he introduced in Investigations V. Published separately, Investigations VI is devoted to two major epistemic distinctions, both couched in the language of mental acts. One is a distinction between meaning-intending acts and meaning-fulfilling acts, the other is a distinction between sensuous intuitions and categorial intuitions. Neither, on the face of it, looks particularly logical. But the distinctions at the conclusion of the Investigations are, for Husserl, logically relevant material. One reason is that the Husserlian account of consciousness was meant to answer a basic question about the normativity of the sciences. In a variety of places Husserl claimed that the theory of mental acts, the new phenomenology, is the foundation for higher-order normative sciences, including ethics and aesthetics, but especially logic. Insofar as logic is not merely a matter of minding one's P's and Q's, but also encompasses the norms governing belief acquisition, and insofar as the conclusion of the Logical Investigations provides an account of judgment as a central part of its theory of consciousness, then the Investigations provides an answer to why we ought to believe logically. This is one way that the Logical Investigations may be read as logical investigations: they are investigations into the theoretical foundations of logic as a normative science.