11. This sets the distinction between philosophy from other sciences. All other sciences concern themselves with a particular object of investigation. a. principle of identity b. study of all things c. reasons, causes & principles d. natural light of reason 12. A thing is either is or is not; everything must either be or not be; between being and not-being, there is no middle ground. a. principle of sufficient reason b. principle of non-contradiction c. principle of identity d. principle of excluded middle 13. They study human beings, society, religion, language, and God among others. a. philosopher b. linguists c. anthropologists d. theologians 14. Philosophy is not based on mere opinion or theories or hypothesis; it is based on certain knowledge derived from reasoned demonstration of causes and reduced to a system. a. natural light of reason b. science c. study of all things d. highest principle 15. Philosophy does not base its knowledge on authority, but solely on the reasoning power of the human mind. a, natural light of reason b. science c. study of all things d. highest principle​