Reading to oneself is a modern activity which was almost unknown to the scholars of the classical and medieval worlds. During the 15th century the term "reading"undoubtedly meant reading aloud. Only during the 19th century did silent reading become common.
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Towards the end of last century there was still considerable argument over whether books should be used for information or treated respectfully, and over whether the reading of material such as newspapers was in some way mentally weakening. Indeed this argument remains with us still in education.However, whatever its virtues were, the old shared literacy culture had gone and was replaced by the printed mass media on the one hand by books and periodicals for specialized readers on the other.
第二段中meantally weakening在这里怎么理解？

“mentally weakening”意思为慢慢让人们从思想上越来越不重视。