As a Christian, how much can we ‘outsource’ (rely on historical account, science, etc.), and how much scripture needs to be included to refute these heresies?

  

In our lives, we may ‘outsource’ our faith. Today’s society teaches humanism, creationism, and so many other issues as truth. As a Christian, how much can we ‘outsource’ (rely on historical account, science, etc.), and how much scripture needs to be included to refute these heresies? Must be 250 words with citation