These axioms were of great interest to Husserl, who in his Lectures on Ethics and Value Theory elaborated the project of a formal axiology as such, Brentano having finally confined himself to proposing axioms.

Husserl raises the hypothesis of an analogy between theoretical, or judicative, reason and practical reason. If we draw a parallel between logic and ethics, and the types of reason to which these disciplines essentially relate - namely, judicative and practical reason - the thought then arises that to logic, in the narrowly defined sense of a formal logic, must also correspond in parallel a formal and also aprioristic practice in an analogous sense ¹.
For Husserl, the sphere of praxis encompasses both ethics and evaluation, in the broadest sense. This leads to the Idea of a formal axiology as a formal aprioristic discipline of values, or of value contents and value meanings - a discipline which, for essential reasons, is intimately intertwined with that of formal praxis ².

In order to see whether the analogy between the theoretical and practical spheres can be verified, we need to find out whether formal ethical and axiological laws can be uncovered.

It is therefore a question of formalising axiology, which means, as D. Pradelle sums it up, abstracting from any contentual or material determination of values, emptying their content in order to consider only the empty value-form of value in general ³.

One of Husserl's results is that the law of excluded middle (either a door is open or it is closed (A or non-A), there is no third solution) is not found in formal axiology. Instead, we find the principle of the excluded quarter: either something has a positive value, or it has a negative value, or it has no value: In the axiological domain there are three fundamental modalities of value - positive value, negative value and null or indifferent value (adiaphoron) ⁴.
Husserl therefore proposed a number of formal axiological laws, often based on Brentano's, such as the following: a pure good is more valuable than a good mixed with an evil. However, we need to return to the examination of formal axiology as a general project, rather than moving on to the study of the specific results it was able to achieve.

1. Lectures on Ethics and Value Theory, Section 1, §1
2. Ibid.
3. Ibid, preface
4. Ibid.