This idea is repeated and explained in other parts of the same work. The sciences, studies and arts developed up to now, says Vico, deal with particular objects: the New Science, on the other hand, investigating as it does the principles themselves which lie at the source of all studies, is able to establish the ἀκμή or state of perfection of the entire system, and the degrees and extremes by which and within which human nature like all other mortal things must run its course and come to an end: so that through this science we can answer the practical questions how a nation in its rise may come to its state of perfection, and how in its decadence it may be stimulated to new life. The state of perfection would consist in a nation's resting upon fixed principles both demonstrated by unchanging reason and put into practice by human habits; principles in which the esoteric wisdom of the philosopher would extend a helping hand to the common wisdom of nations, thus uniting men of the greatest academic reputation with all those of wisdom in the state, the philosophers with the statesmen; and the science of civil matters divine and human, religion and law, a theology and morality imposed by command and acquired by habituation, would be supplemented by the science of natural laws divine and human, a theology and morality imposed by reason and acquired by ratiocination: so that to transgress such principles would be true error, the wandering not of men but of wild animals.
The practical aspect of the New Science, then, was simply a summary or duplicate of the science itself, emphasising the two leading elements of spontaneous and reflective wisdom, certitude and truth, and the necessity of bearing both in mind.
Years later, in one of the elaborations of the second _Scienza Nuova_ made by Vico, we again meet with the idea and the phrase of a practical aspect of this science, in the title of a special concluding paragraph which he proposed to add to his work. It begins thus: "The whole of this work has now been thought out as a mere contemplative science dealing with the common character of nations: for this reason it may seem to offer no assistance to human prudence in order either to prevent or to delay the entire ruin of nations on the path of decadence, and thus to lack the practical side which every science must have whose subject-matter is dependent upon the human will, all such sciences being called practical." Now in what could such a practical side consist? "This practical application can easily be found from the contemplation itself of the course of the history of nations: which the wise men (statesmen) and princes of states observing, could by means of good ordinances, laws and examples recall peoples to their ἀκμή or state of perfection." In other words: a man warned is half saved. Contemplation is the only principle of conduct which the New Science can supply. The other half of salvation depends not on the person warning, namely thought, but upon the person warned, upon action. It does not occur to Vico to try to determine the "ordinances, laws and examples" whose adoption would be of value in this or that crisis or situation. This would not be a philosopher's task, as in fact he himself clearly recognises next moment, when he says: "The only practical principles we philosophers can supply are ones which can be confined to the academic sphere."