I do not believe today everything I believed yesterday; I wonder will I believe tomorrow everything I believe today.

The speaker reflects on the instability of conviction over time: beliefs once held with confidence can be revised or abandoned as experience, evidence, and reflection accumulate. The second clause turns that observation into a forward-looking skepticism—if yesterday’s certainties proved provisional, today’s may be equally so. The line can be read as an argument for intellectual humility and openness to change, but also as a portrait of modern doubt: the mind’s inability to rest in fixed dogma. In an Arnoldian key, it resonates with the pressures of a rapidly changing intellectual climate, where inherited religious and moral frameworks are continually tested by new knowledge and criticism.