Gingest du über eine Ebene, hättest den guten Willen zu gehen und machtest doch Rückschritte, dann wäre es eine verzweifelte Sache; da du aber einen steilen Abhang hinaufkletterst, so steil etwa, wie du selbst von unten gesehen bist, können die Rückschritte auch nur durch die Bodenbeschaffenheit verursacht sein, und du mußt nicht verzweifeln.
If you were walking across a plain, had an honest intention of walking on, and yet kept regressing, then it would be a desperate matter; but since you are scrambling up a cliff, about as steep as you yourself are if seen from below, the regression can only be caused by the nature of the ground, and you must not despair. [Kaiser/Wilkins]
If you were walking across a plain, felt every desire to walk, and yet found yourself going backward, it would be a cause for despair; but as you are in fact scaling a steep precipice, as sheer in front of you as you are from the ground, then your backward movement can be caused only by the terrain, and you would be wrong to despair. [Hofmann]
The is one of the aphorisms Kafka struck out, but which editorial obstinacy includes in these editions and this blog anyway.
Your despair is a mistake. It would make sense if you were trying and failing to make progress, but, as it is, the difficulties arise from without. So the error lies in mistaking the mountain for the plain, and what is outside you for what is inside you.
The despair in the initial example is dreamlike, because there is no accounting for your going backward as you plainly move forward. Your intention is honest, so there is no question of anything like subconscious resistance. If you face bewildering setbacks, then despair is a reasonable reaction, isn't it? On the other hand, if there is an obvious and natural reason for your difficulties, then despair is unreasonable, because no one else could do what you're trying to do either.
Where are you going? If walking is all you want to do, then walking backward is as good as walking forwards. If this is the true way mentioned in the first aphorism, then this would be another representation of precariousness, instability or uncertainty, presented in combination with going back imagery from the fourth and fifth aphorisms. You have to keep going until you stop going back.
This aphorism also touches on point of view, since the cliff is as steep as you are seen from the ground. It's strange that Kafka chooses you for the simile of something steep, and implies for this purpose another person, looking up at you from below, as if you were the cliff he were climbing. This kind of reflecting-back is really typical of Kafka. He claimed he could never accuse anyone of anything without having it rebound back and attach itself to him instead. It might be that this aphorism is cancelled, because he doesn't really believe the steepness is in the ground.