“There is no steady unretracing progress in this life; we do not advance through fixed gradations, and at the last one pause: through infancy's unconscious spell, boyhood's thoughtless faith, adolescence' doubt”

Simplified Meaning:

Life doesn't follow a straight path or move forward in clear steps. We don't go from one stage to the next in a predictable way and then stop progressing. For example, when you're a baby, you don't know much about the world and just start discovering things. As a child, you might believe in things easily without questioning them. But when you become a teenager, you start to question everything and have doubts. In real life, think about learning a new skill like playing the piano. At first, you fumble around, not knowing where the keys are. With more practice, you play simple songs and feel confident. But as you aim for harder pieces, you might face new challenges that make you doubt your abilities. The idea is that we all go through various phases and challenges at different times. Instead of thinking that life is about climbing a ladder step by step, understand that it's more like a winding path with ups and downs, where you have to keep adjusting and learning at every stage. Expect change and growth in an unpredictable rhythm, and don’t be discouraged when things don't go in a straight line.