We can mistrust the senses. Indeed they deceive us all the time. However, we should avoid solipsism.
Other things exist, and we can assume this legitimately, namely, from the act of reading. Reading is a physical and mental act that ratifies the former in the face of the latter. Consider this, to read you have to see [or feel, e.g. in Braille] letters, words, and phrases [while simultaneously in the act of touching/holding a book]. If senses were deceiving and there was not a good reason to believe them, we would not know if, in fact, objects are truly real or just tricks of the senses. However, books seem to trump this issue.
Why is this? Because something written often contains information, and when you do not know that information, it enters your mind once you read it [see, feel, touch—physical] and understand it [mental]. Now how could something foreign enter your mind if it does not exist? The fact that I know now the capital and population of Country X is not something innate, it invaded my mind—because of a physical act [reading]. Now this would entail that my senses were not deceived, there was in fact a book, I saw the right words, and that is why I am informed.
The external should be real. Solipsism may just be a myth. This, anyway, legitimates the power of the senses to about the same degree as self-knowledge, but is ultimately dependent upon it.
