It follows that the Jewish national idea and the national feeling connected with it have their origin primarily in the historical consciousness, in a certain complex of ideas and psychic predispositions. These ideas and predispositions, the deposit left by the aggregate of historical impressions, are of necessity the common property of the whole nation, and they can be developed and quickened to a considerable degree by a renewal of the impressions through the study of history. Upon the knowledge of history, then, depends the strength of the national consciousness.[5] [5] A different aspect of the same thought is presented with logical clearness in another publication by our author. "The national _idea_, and the national _feeling_," says Mr. Dubnow, "must be kept strictly apart. Unfortunately the difference between them is usually obliterated. National feeling is spontaneous. To a greater or less degree it is inborn in all the members of the nation as a feeling of kinship. It has its flood-tide and its ebbtide in correspondence to external conditions, either forcing the nation to defend its nationality, or relieving it of the necessity for self-defense. As this feeling is not merely a blind impulse, but a complicated psychic phenomenon, it can be subjected to a psychologic analysis. From the given historical facts or the ideas that have become the common treasure of a nation, thinking men, living life consciously, can, in one way or another, derive the origin, development, and vital force of its national feeling. The results of such an analysis, arranged in some sort of system, form the content of the national idea. The task of the national idea it is to clarify the national feeling, and give it logical sanction for the benefit of those who cannot rest satisfied with an unconscious feeling.