A Row of Steps

There was a row of steps which led upwards or downwards, depending on which way you looked at them, or indeed which way you were going. If going upwards they led upwards, if downwards then downwards. But the steps themselves of course didn't go anywhere. They were entirely stationary. It was merely the beings who used them who would be going up or down. Though admittedly, given the modern world, perhaps there should be no of course about these steps' immobility. But anyway these were old-fashioned steps and didn't move about.

But these steps were not quite what one might wish them to be for though they looked solid enough, as soon as one put one's foot on one it would begin to crumble, and so one would have to move quickly onto the next which in turn would behave in the same disintegratory manner, and so on and on one would be forced to go so as to avoid collapse with the crumbling rubble. So if you were intending on going upwards that is the direction you had better set out in, lest, having gone for some reason downwards- perhaps on a whim- you find between yourself and your destination only the memories of steps, as it were, rather than steps.

It would of course be alot easier, in this absence of steps, to descend from above to below rather than ascend from below to above; descent merely involving a movement into freefall whilst ascent involving an altogether more involved and arduous process, and the deeper the descent the more difficult the upwards journey becomes, perhaps even to the ultimate point of absolute impossibility.
Do the steps downwards and upwards continue infinitely or at last end in a final step which crumbles beneath one's weight? I can't say as I know.