I invite all such to join themselves, as true sons of knowledge, with me, that passing by the outer courts of nature, which Numbers have trodden, we may find a way at length into her inner Chambers.

A string whose length is greater than zero is always evaluated as True when resolved to a Boolean function, even if its value is the string 'false'.

For instance, you can see that any time the if condition is true, the nested while loop will execute at least one time (because the list length will be greater than zero).