  More doubts about the strict simplicity of Forms emerge from reflection on the nature of definition in Plato's middle period. Ontologically, all definitions predicate the essence of the Form whose essence it is. Plato is attempting to discover through scientific investigation, or (inclusive or) through an analysis of what words mean, or through any other method, what the nature of, say, Justice  is—compare the ways in which philosophers and scientists work to discover what, e.g., gold, or red, or justice, is. Ultimately, then, the answer to any ‘what is X?’ question will be some specific formula unearthed at the end of much study. According to this line of reasoning, the self-predication statements in the texts are promissory notes, shorthand for what will turn out to be the fully articulated definition. Plato is thus committed to there being Forms whose nature or essence will ultimately be discovered. To say that ‘Justice is just’ is then to stake a claim to the ultimate discovery of the nature of Justice. The problem is that the fully articulated linguistic definition, when it is ultimately discovered, will turn out to be complex. For instance, Heat, one thing, is mean molecular kinetic energy, a seemingly complex notion. So in Plato we find (Republic, 441d) that Justice is Doing One's Own, that a Name is (Cratylus, 388b) a tool that is informative and separates nature, or, though Plato never says it, that Human is rational bipedal animal. Since philosophical and (scientific progress) is supposed to teach not that Justice is just but what Justice is, at some level at least Forms cannot be considered to be utterly and strictly simple. The problem is that given just two predication relations, it is unclear whether Plato thinks that Forms partake of the properties to which they are related or whether they are those properties.