As an academic investigation, Logic can be called the systematic investigation of argumentation (an argument being a linguistic articulation of rational thought). There are two distinct systems of argumentation:
While rational argument, or logic, is the fundamental characteristic distinguishing early Philosophy from religion or Mythology (the narrative account of the world rooted in the belief that causality is determined by invisible forces [i.e., gods, ancestors, spirits, etc.] that are beyond ordinary human comprehension) it was not until Aristotle that any philosopher attempted a systematic explanation of just how logic works. Since Aristotle, philosophers have continuously explored the nature of reason and have developed more and more complex logical systems (both formal and informal).
Computer program languages (or ‘codes’) are one contemporary practical application of logic beyond the academic fields of inquiry.