Final answer:
Thomas Hobbes claimed that in the absence of law, existence would be a 'war of all against all'.
Step-by-step explanation:
The philosopher who claimed that in the absence of law, existence would be a 'war of all against all' is Thomas Hobbes. Hobbes argued that without a governing authority, society would descend into chaos and conflict. He proposed the concept of a social contract, where individuals would give up some of their freedom in exchange for protection and security from a centralized government.
In his seminal work, Leviathan, Hobbes presented the idea of a social contract where individuals would surrender some of their freedoms to a strong, absolute ruler, or Leviathan, to avoid living in a perpetual state of chaos and warfare. This governmental entity would enforce the laws of nature and maintain peace and order.