According to the Principle of Formal Justice like cases must be treated alike, and different cases must be treated differently. This principle is derived from the Aristotelian concept of distributive justice. Aristotle held that ‘All men agree that what is just in distribution should be according to merit of some sort, but not all men agree as to what that merit should be’. The classical concept of illegal discrimination, in Community law referred to as direct discrimination, seeks to decide what these merits must not be. This is done by declaring disparate treatment on certain grounds, in certain circumstances, illegal. It is argued in this paper that exceptions to this principle are made through acknowledging that discriminations on prohibited grounds are sometimes justified, and that this should be called justified direct discrimination. It is submitted that it is only obscuring to the concept to suggest otherwise, since the concept of discrimination as such, just as the Principle of Formal Justice, should not be carrying substantive or emotive meanings. The subsequent concept of indirect discrimination aims instead at prohibiting disparate impacts of neutral criteria. There is some ambiguity to this concept, specifically on what it is that amounts to ‘discrimination’ in this context, and how the available defences should be perceived. It is submitted that to pursue clarity, it must be acknowledged that this concept is built on the second element of the Principle of Formal Justice, i.e., that different cases must be treated differently, and that ‘discrimination’ occurs when discriminators omit to do so, causing disparate impacts statistically connected to prohibited grounds of discrimination. A justification defence, if successful, should in such circumstances prompt courts to hold that there has been discrimination, but that it is justified. It is further argued that the concept of positive action is a formal concept through which disparate treatment is required on specific grounds, i.e., that the legislature in this case indeed recognises some ‘merits’ according to which distribution is ‘just’ (according to the legislature). Unlike direct and indirect discrimination, positive action is necessarily a one-way vessel, designed to promote preference for individuals belonging to a certain class of people identified by the positive action norm. The author concludes that all these concepts are built upon a formal structure taken from the Principle of Formal Justice, and that the acknowledgment of this fact can contribute to clarity in anti-discrimination law.