Magritte's This is Not a Pipe

Michael Foucault tries to explain the meaning behind Rene Magritte's painting, "This is Not a Pipe." The painting itself is of a well rendered depiction of a pipe, yet beneath the pipe is painted "This is not a pipe." Foucault states that the most obvious explanation for this is that it is an illustration of a pipe and therefore is not a "real" pipe. However, Foucault is not satisfied with this answer and believes that there is something more to the illustration and the sentence.
If the sentence is read at face value, there are three possible outcomes. Either the illustration is not a "real" pipe, the sentence itself is not a pipe, or the sentence and the illustration together is not a pipe. In all of these interpretations the illustration is still not a pipe.


Question: Foucault says that the illustration of the pipe and the writing should be viewed together, but is that really possible? Humans naturally read and connect the sentence with the illustration. I know Magritte probably had that in mind when creating this piece, but it is all very confusing.