Herein, then, lies the difference between judgments of fact and judgments of value. The mineralogist can train his pupil to see precisely what he himself sees; and so likewise in any case of sense-perception, the object, however recondite may be the qualities or features which one may see in it, _can_ nevertheless be seen by any other person in precisely the same way on the single, more often not insuperably difficult, condition that the discoverer shall point these out or otherwise prepare the other for seeing them. But with the ton of coal which one may judge economically disposable for a charitable purpose the case stands differently, since it is not in its visible or other physical aspects that the ton of coal is here the subject of the judgment. It is as having been set apart _by oneself exclusively_ for other uses that the ton of coal now functions as an object and now possesses the character which the economic judgment has given it; and the case stands similarly with a contemplated act, of telling the truth in a trying situation. The valuation placed upon the commodity or upon the moral act depends essentially upon psychological conditions of temperament, disposition, mood, or whim into which it would be impossible for another person to enter, and these depend upon conditions of past training and native endowment which can never occur or be combined in future in precisely the same way for any other individual. In short, the physical object is _describable_ and _can_ be made socially current, though doubtless with more or less of difficulty, if other persons will attend to it and learn to see it as I see it; but the value of an economic object or a moral act depends upon my desires and feelings, and therefore must remain a matter of my private appreciation.