古い(ふるい)習慣(しゅうかん)に縛られず(しばられず)に、物事を(ものごとを)「疑う(うたがう)心(こころ)」を持ち(もち)新しいことに挑戦する

Furthermore, Yukichi explained that learning is not merely reading old books and being satisfied, but critically observing the mechanisms of society and world trends. Instead of just obeying old customs, he passionately said that having a 'spirit of doubt' toward things and challenging new ideas is what makes modern society progress.