His chief works are Philosophie als Denken der Welt gem[iss dem Princip des kleinsten Kraftmasses (1876) and the Kritik der reinen Erfahrung (1888-1890).
Reinen Erfahrung (1900).
In Kant's Analogien der Erfahrung (1876) he keenly criticized Kant's transcendentalism, and in his chief work Idealismus and Positivismus (3 vols., 1879-1884), he drew a clear contrast between Platonism, from which he derived transcendentalism, and positivism, of which he considered Protagoras the founder.
Cohen his more important Kants Theorie der Erfahrung, which led Lange to modify his interpretation of Kant in the second edition of his own book.
In his first philosophical treatise, Philosophie als Denken der Welt gemdss dem Princip des kleinsten Kraftmaasses, Prolegomena zu einer Kritik der reinen Erfahrung (1876), he based his views on the principle of least action, contending that, as in Nature the force which produces a change is the least that can be, so in mind belief tends in the easiest direction.
Afterwards, in his Kritik der reinen Erfahrung (1888-1890), Avenarius aimed at giving a description of pure experience which he identified with the natural view of the world held by all unprejudiced persons.
It therefore to some extent assumes from the first the position which it proposes ultimately to reach, and gives, not a proof of that position, but an account of the experience (Erfahrung) by which consciousness is forced from one position to another till it finds rest in Absolutes Wissen.