These axioms deeply interested Husserl, who, in his Lectures on Ethics and Value Theory, expanded upon the project of formal axiology, whereas Brentano had ultimately limited himself to simply proposing axioms.

Husserl posits a hypothesis suggesting an analogy between theoretical (or judicative) reason and practical reason. Drawing a parallel between logic and ethics, and the types of reason associated with these disciplines—namely, judicative and practical reason—he introduces the idea that, alongside 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 realm of praxis includes both ethics and evaluation in their broadest forms. 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.

To evaluate whether the analogy between the theoretical and practical spheres is valid, we must ascertain whether formal ethical and axiological laws can indeed be discovered.

The task, then, is to formalise axiology, which, as summarised by D. Pradelle, involves abstracting from any specific or material determination of values, stripping them of content to examine only the bare value-form of value itself ³.

One of Husserl’s findings is that the law of excluded middle—either a door is open or closed (A or non-A), with no third option—does not apply in formal axiology. Instead, he introduces the principle of the excluded quarter: something may have a positive value, a negative value, or no value at all. In the axiological domain, there are three fundamental value modalities—positive value, negative value, and null or indifferent value (adiaphoron) ⁴.

Husserl thus proposed several formal axiological laws, often drawing from Brentano’s work, such as: a pure good is more valuable than a good mixed with evil. However, we must return to examining formal axiology as a broader project rather than delving into the specific results it has managed to achieve.

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