 The adoption of this fourfold ontology allows Socrates to assign the two contenders for best condition in human nature to two of the four classes: pleasure turns out to be unlimited, because it admits of the ‘more and less ’. Reason, by contrast, belongs to the fourth class, as the cause of good mixtures. On the basis of this classification, Socrates’ investigation provides a critical assessment of different kinds of pleasure and knowledge (31b–59d). It turns out that pleasure is at best a remedial good: pleasure is always the filling of a lack, or the restoration of a harmonious state, and therefore pleasure presupposes some kind of disturbance of the physical or mental equilibrium. A pleasure may be false, harmful or violent if its pursuer is mistaken about the object’s identity and quantity, or if there is no real cure for the disturbance. A pleasure may be ‘true and pure’ if it is a compensation for a harmless and unfelt lack, and if its possessor is not mistaken about the nature of its object (31b–55c). The rivals of the pleasures – the different intellectual disciplines – also vary in quality; but in their case the difference in quality depends on the amount of mathematical precision they contain (55c–59d). The decision about what mixture will make for a happy life leads to a combination of the true and pure pleasures with all the kinds of knowledge and disciplines that are necessary for life’s needs (59d–64b). In the final ranking of goods, measure and due proportion, unsurprisingly, get the first rank, things in proper proportion come in second, reason is ranked third, the arts and sciences obtain fourth place, whereas the true and pure pleasures get fifth and last place on the scale of goods (64c–67b). If Plato in the Philebus is more favorably disposed towards a hedonist stance than in some of his earlier works, he is so only to a quite limited degree: he regards pleasure as a necessary ingredient in human life, because both the physical and the psychic equilibria that constitute human nature are unstable. There is always some deficiency or lack that needs supplementing. Because the range of such ‘supplements’ include learning and the pursuit of the virtues, there are some pleasures that are rightly cherished. But even they are deemed goods only because they are compensations for human imperfection.