For the source text click/tap here: Gittin 52
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It is related that there was a certain steward who was in Rabbi Meir’s neighborhood who was selling land belonging to the orphans and purchasing slaves with the proceeds, and Rabbi Meir did not allow him to do this, as the practice is contrary to halakha. They showed him in his dream the words: I wish to destroy and you build? He understood this as a sign that God wanted the orphans to suffer financial collapse, and therefore it would be preferable to allow the steward to continue his practice. Even so, Rabbi Meir paid no heed to his dream, and said: Words appearing in dreams do not bring up and do not take down; they should not be taken into consideration.
The Talmud contains many theories about the content of dreams. In Berachot (10b) Rabbi Hanan taught that even if a dream appears to predict one's imminent death, the one who dreamed should pray for mercy. R. Hanan believed that dreams may contain a glimpse of the future, but that prayer is powerful enough to changes one's fate.
Later in Berachot (55b), R. Yohanan suggests adifferent response to a distressing dream: let the dreamer find three people who will suggest that in fact the dream was a good one (a suggestion that is codified in שולחן ערוך יורה דעה 220:1).
In contrast, Rabbi Yonatan suggests that dreams do not predict the future: rather they reflect the subconscious (Freud would have been proud). "R. Yonatan said: a person is only shown in his dreams what he is thinking about in his heart..." (Berachot 55b).
And from our daf , we learn that Rabbi Meir believed dreams were of no consequence whatsoever.