properly instructed person can expect any fixity in it, or complain of injustice merely on account of the variations in it. Can we then say that ‘market value’ (as determined by free competition) corresponds to our notion of what is ideally just? This is a question of much interest, because this is obviously the mode of determining the remuneration of services that would be universal in a society constructed on the principle previously discussed, of securing the greatest possible Freedom to all members of the community. It should be observed that this, which we may call the Individualistic Ideal, is the type to which modern civilised communities have, until lately, been tending to approximate: and it is therefore very important to know whether it is one which completely satisfies the demands of morality; and whether Freedom, if not an absolute end or First Principle of abstract Justice, is still to be sought as the best means to the realisation of a just social order by the general requital of Desert. At first sight it seems plausible to urge that the ‘market value’ represents the estimate set upon anything by mankind generally, and therefore gives us exactly that ‘common sense’ judgment respecting value which we are now trying to find. But on examination it seems likely that the majority of men are not properly qualified to decide on the value of many important kinds of services, from imperfect knowledge of their nature and effects; so that, as far as these are concerned, the true judgment will not be represented in the market-place. Even in the case of things which a man is generally able to estimate, it may be manifest in a particular case that he is ignorant of the real utility of what he exchanges; and in this case the ‘free’ contract hardly seems to be fair: though if the ignorance was not caused by the other party to the exchange, Common Sense is hardly prepared to condemn the latter as unjust for taking advantage of it. For instance, if a man has discovered by a legitimate use of geological knowledge and skill that there is probably a valuable mine on land owned by a stranger, reasonable persons would not blame him for concealing his discovery until he had bought the mine at its market value: yet it could not be said that the seller got what it was really worth. In fact Common Sense is rather perplexed on this point: and the _rationale_ of the conclusion at which it arrives, must, I conceive, be sought in economic considerations, which take us quite beyond the analysis of the common notion of Justice.[226] Again, there are social services recognised as highly important which generally speaking have no price in any market, on account of the indirectness and uncertainty of their practical utility: as, for instance, scientific discoveries. The extent to which any given discovery will aid industrial invention is so uncertain, that even if the secret of it could be conveniently kept, it would not usually be profitable to buy it.