There is a limit where the intellect fails and breaks down, and this limit is where the questions concerning God and freewill and immortality arise.
Laws always lose in energy what the government gains in extent.
Thrift is care and scruple in the spending of one's means. It is not a virtue and it requires neither skill nor talent.
So act that anything you do may become universal law.
Live your life as though your every act were to become a universal law.
Philosophy stands in need of a science which shall determine the possibility, principles, and extent of human knowledge à priori.