The social temper, therefore, will become far more intelligent and reasonable than it has been hitherto. It will be slow to dogmatize, and will regard the _toleration_ of differences of opinion as among the cardinal principles of a sanely progressive social order. For as we can no longer assume, with Plato and the other Utopians, that _perfection_ may be postulated, provision has always to be made for the _improvement_ of the social order. It can never be accepted as absolutely good, but must always be regarded as capable, in principle, of being bettered. Even the best of established institutions are only good relatively to the alternatives to which they showed themselves superior: under changed conditions they may become inferior, and may fail us, or ruin us, if we do not make haste to transform them into something better fitted to the new conditions. Hence the social order must be _plastic_, and must never be allowed to grow rigid. There must always be room in it for experiments that have a reasonable prospect of turning out to be improvements. For progress will depend on the timely adoption of such novelties. But society has no means of commanding them at will. It has to wait till they occur to some one. As biological variations have to arise spontaneously before they can be selected, so valuable new ideas have to occur in a human mind before they can be tried and approved. Society cannot originate discoveries, it can only refrain from so organizing itself as to stamp them out when they occur. It is vitally necessary, therefore, that we should beware of suppressing variations, whether of thought or of bodily endowment, that may prove to be valuable. Also, of course, we shall have to realize that our whole procedure is _essentially experimental_, and all that this implies. We do not know, at the outset, what would be the best obtainable type, either of man or of society; true, but we mean to find out. Nor is it unreasonable to expect to do so as we go along. We start with a pretty shrewd suspicion that certain types, say the feeble-minded, the sickly, the insane, are undesirable, and that no good can come of coddling and cultivating them: we similarly are pretty sure that certain other types, say the intelligent, healthy, and energetic, are inherently superior to the former. We try, therefore, to improve and increase the better types. How precisely, and how most effectively we do not quite know, though we can make pretty good preliminary guesses. So we try. That will entail experimentation in a variety of directions, with ‘control experiments,’ and a modicum of mistakes. But our mistakes will not be fatal, because if we advance tentatively and with intelligent apprehension, we shall realize them in time, and shall not feel bound to persist in any course that yields unsatisfactory results.