of course , like druids everywhere they believed in the essential unity of all life , the healing ower of plants , the natural rhythm of the seasons and the burning alive of anyone who did n't approach all this in the right frame of mind , but they had also thought long and hard about the very basis of creation and had formulated the following theory : the universe , they said , depended for its operation on the balance of four forces which they identified as charm , persuasion , uncertainty and bloody-mindedness .