Information is weird like that. It is its own ailment, its own deficiency, its own excess, its own cure. You flush out bad information with more (different) information. You fill a gap in information with more information. Programmers (and geneticists?) know: you could be just one character, one punctuation mark away from heaven.
We never see how the Doctor began his journey, we will probably never see how he ends it, we’ll probably never know why he embarked on it but we know all those companions who they were before they met the Doctor. The story is always about the person who changes the most rather than necessarily about the person who does the most – who effects those changes.
