In 1933, under racial laws of the Nazi Party, Husserl was expelled from the library of the University of Freiburg due to his Jewish family background and months later resigned from the Deutsche Akademie.

Then professor Weierstrass became very ill. Husserl became free to return to Vienna where, after serving a short military duty, he devoted his attention to philosophy.

During this period Husserl had delivered lectures on internal time consciousness, which several decades later his former students Edith Stein and Martin Heidegger edited for publication.

There has been a debate over whether or not Husserl's description of ownness and its movement into intersubjectivity is sufficient to reject the charge of solipsism, to which Descartes, for example, was subject.

[21] Later Husserl lectured at Prague in 1935 and Vienna in 1936, which resulted in a very differently styled work that, while innovative, is no less problematic: Die Krisis (Belgrade 1936).

[43][44] Husserl describes here the cultural crisis gripping Europe, then approaches a philosophy of history, discussing Galileo, Descartes, several British philosophers, and Kant.

Such observations of Heidegger, along with a critique of Max Scheler, were put into a lecture Husserl gave to various Kant Societies in Frankfurt, Berlin, and Halle during 1931 entitled Phänomenologie und Anthropologie.

[52][53] In the war-time 1941 edition of Heidegger's primary work, Being and Time (Sein und Zeit, first published in 1927), the original dedication to Husserl was removed.

This was not due to a negation of the relationship between the two philosophers, however, but rather was the result of a suggested censorship by Heidegger's publisher who feared that the book might otherwise be banned by the Nazi regime.

[56]After his death, Husserl's manuscripts, amounting to approximately 40,000 pages of "Gabelsberger" stenography and his complete research library, were in 1939 smuggled to the Catholic University of Leuven in Belgium by the Franciscan priest Herman Van Breda.

Husserl tries new methods of bringing his readers to understand the importance of phenomenology to scientific inquiry (and specifically to psychology) and what it means to "bracket" the natural attitude.

In it, Husserl for the first time attempts a historical overview of the development of Western philosophy and science, emphasizing the challenges presented by their increasingly one-sidedly empirical and naturalistic orientation.

Husserl declares that mental and spiritual reality possess their own reality independent of any physical basis,[64] and that a science of the mind ('Geisteswissenschaft') must be established on as scientific a foundation as the natural sciences have managed: "It is my conviction that intentional phenomenology has for the first time made spirit as spirit the field of systematic scientific experience, thus effecting a total transformation of the task of knowledge.

In the former, sense-perception in correspondence with the material realm constitutes the known reality, and understanding is premised on the accuracy of the perception and the objective knowability of what is called the "real world".

Thanks to "eidetic reduction" (or "essential intuition"), people are able to grasp the possibility, impossibility, necessity and contingency among concepts and among formal categories.

In formal ontology, it is a free investigation where a mathematician can assign several meanings to several symbols, and all their possible valid deductions in a general and indeterminate manner.

Through the posit of certain indeterminate objects (formal-ontological categories) as well as any combination of mathematical axioms, mathematicians can explore the apodeictic connections between them, as long as consistency is preserved.

Some scholars question whether Frege's negative review of the Philosophy of Arithmetic helped turn Husserl towards modern Platonism, but he had already discovered the work of Bernard Bolzano independently around 1890/91.

Scholars such as J. N. Mohanty, Claire Ortiz Hill, and Guillermo E. Rosado Haddock, among others, have argued that Husserl's so-called change from psychologism to Platonism came about independently of Frege's review.

Frege's attack seems to be directed at certain foundational doctrines then current in Weierstrass's Berlin School, of which Husserl and Cantor cannot be said to be orthodox representatives.

Reacting against authors such as John Stuart Mill, Christoph von Sigwart and his own former teacher Brentano, Husserl criticised their psychologism in mathematics and logic, i.e. their conception of these abstract and a priori sciences as having an essentially empirical foundation and a prescriptive or descriptive nature.

Pure logic does not deal at all with "thoughts" or "judgings" as mental episodes but about a priori laws and conditions for any theory and any judgments whatsoever, conceived as propositions in themselves.

"[98] He was an original editor of Husserl's new journal, Jahrbuch; one of his works (giving a phenomenological analysis of the law of obligations) appeared in its first issue.

"[100] Edith Stein was Husserl's student at Göttingen and Freiburg while she wrote her doctoral thesis The Empathy Problem as it Developed Historically and Considered Phenomenologically (1916).

Landgrebe is known as one of Husserl's closest associates, but also for his independent views relating to history, religion and politics as seen from the viewpoints of existentialist philosophy and metaphysics.

Scheler, who was at Göttingen when Husserl taught there, was one of the original few editors of the journal Jahrbuch für Philosophie und Phänomenologische Forschung (1913).

In 1921 the prestige of Hartmann the Neo-Kantian, who was Professor of Philosophy at Marburg, was added to the Movement; he "publicly declared his solidarity with the actual work of die Phänomenologie."

Merleau-Ponty's description of 'motor intentionality' and sexuality, for example, retain the important structure of the noetic/noematic correlation of Ideen I, yet further concretize what it means for Husserl when consciousness particularizes itself into modes of intuition.

Colin Wilson has used Husserl's ideas extensively in developing his "New Existentialism," particularly in regards to his "intentionality of consciousness," which he mentions in a number of his books.

It has already started to impact (indirectly) scholarship in Eastern and Oriental thought, including research on the impetus of philosophical thinking in the history of ideas in Islam.