In the article I deal with some paradoxes and errors caused by improper usage of logical and philosophical terms appearing in the arguments for existence of God and other philosophical issues. I point at first some paradoxes coming from improper usage of propositional calculus as an instrument for analysis of a natural language. This language is actually not using simple sentences but rather propositional functions, their logical connections, and some replacements for variables in them. We still have to deal with so called paradox of material implication. The second paragraph provides formal and metatheoretical critics of Charles Sanders Peirce’s theory of deduction, induction and abduction. I argue that what Peirce and his followers call a...