[I]t being reasonable and just, I should have a right to destroy that which threatens me with destruction: for by the fundamental law of nature, man being to be preserved as much as possible, when all cannot be preserved, the safety of the innocent is to be preferred: and one may destroy a man who makes war upon him, or has discovered an enmity to his being, for the same reason that he may kill a Wolf or a lion.... - John Locke