"Kafka's parable reads as follows:

He has two antagonists: the first presses him from behind, from the origin. The second blocks the road ahead. He gives battle to both. To be sure, the first supports him in his fight with the second, for he wants to push him forward, and in the same way the second supports him in his first with the first, since he drives him back. But it is only theoretically so. For it is not only the two antagonists who are there, but he himself as well, and who really knows his intentions? His dream, though, is that some time in an unguarded moment --and this would require a night darker than any night yet has ever been-- he will jump out of the fighting line and be promoted, on account of his experience in fighting, to the position of umpire in their fight with each other.

...

Seen from the viewpoint of man, who always lives in the interval between past and future, time is not a continuum, a flow of uninterrupted succession; it is broken in the middle, at the point where 'he' stands; and 'his' standpoint is not the present as we usually understand it but rather a gap in time which 'his' constant fighting, 'his' making a stand against past and future, keeps in existence. Only because man is inserted into time and only to the extent that he stands his ground does the flow of indifferent time break up into tenses; it is this insertion --the beginning of a beginning, to put it into Augustinian terms-- which splits up the time continuum into forces which then, because they are forcused on the particle or body that gives them their direction, begin fighting with each other and acting upon man in the way Kafka describes.

...

Obviously what is missing in Kafka's description of a thought-event is a spatial dimension where thinking could exert itself without being forced to jump out of human time altogether. The trouble with Kafka's story in all its magnificence is that it is hardly possible to retain the notion of a rectilinear temporal movement if its unidirectional flow is broken up into antagonistic forces being directed toward each other and acting upon man. The insertion of man, as he breaks up the continuum, cannot but cause the forces to deflect, however lightly, from their original direction, and if this were the case, they would no longer clash head on but meet at an angle. In other words, the gap where 'he' stands is, potentially at least, no simple interval but resembles what the physicists call a parallelogram of forces.
	Ideally, the action of the two forces which form the parallelogram of forces where Kafka's 'he' has found his battlefield should result in a third force, the resultant diagonal whose origin would be the point at which the forces clash and upon which they act. The diagonal force would in one respect differ from the two forces whose result it is. The two antagonistic forces are both unlimited as to their origins, the one coming from and infinite past and the other from an infinite future; but thought they have no known beginning, they have a terminal ending, the point at which they clash. The diagonal force, on the contrary, would be limited as to its origin, its starting-point being the clash of the antagonistic forces, but it would be infinite with respect to its ending by virtue of having resulted from the concerted action of two forces whose origin is infinity. This diagonal force, whose origin is known, whose direction is determined by past and future, but whose eventual end lies in infinity, is the perfect metaphor for the activity of thought. If Kafka's 'he' were able to exert his forces along this diagonal, in perfect equidistance from past and future, walking along this diagonal line, as it were, forward and backward, with the slow, ordered movements which are the proper motion for trains of thought, he would not have jumped out of the fighting-line and be above the melee as the parable demands, for this diagonal, thought pointing toward the infinite, remains bound to and is rooted in the present; but we would have discovered--pressed as he was by his antagonists into the only direction from which be could properly see and survey what was most his own, what had come into being only with his own, self-inserting appearance-- the enormous, ever-changing time-space which is created and limited by the forces of past and future; he would have found the place in time which is sufficiently removed from past and future to offer 'the umpire' a position form which to judge the forces fighting with each other with impartial eye."

Arendt, Hannah. Between Past and Future. New York: Penguin, 1993.

"Due to its size, Boston is a very accessible city, but it may be that its reputation as a walking city relies on the creation of one of America's first historic walking tours, The Freedom Trail.

The Freedom Trail Foundation continues to work to preserve this perfect introduction to Colonial Revolutionary Boston. The Trail takes the visitor to 16 historical sites in the course of two or three hours and covers two and a half centuries of America's most significant past. A red brick or painted line connects the sites on the Trail and serves as a guide."

http://www.cityofboston.gov/freedomtrail/