Open-mindedness should not be fostered because, as Scripture teaches, Truth is great and will prevail, nor because, as Milton suggests, Truth will always win in a free and open encounter. It should be fostered for its own sake.
To see, to hear, means nothing. To recognize (or not to recognize) means everything. Between what I do recognize and what I do not recognize there stands myself. And what I do not recognize I shall continue not to recognize.