Arguments are either conclusive or they are not conclusive. Conclusive arguments are deductive arguments, and are circular; inconclusive arguments are non-deductive and are invalid. Circularity and invalidity are bad things. Arguments that are deductively valid may indeed elucidate the content of the premises, but they do not advance our knowledge in any useful sense, while invalid arguments, to the extent that they can advance knowledge, must be classified as guesses or conjectures, rather than as arguments. In present-day philosophical literature it is common for a distinction to be made between arguments on the one side and inference, reasoning, and argumentation on the other. It is not of course denied that by arguments we often mean argumentation. The rejection of the doctrine that arguments can be used to increase our knowledge evidently depends on a construe of knowledge as something objective; as something we may be in possession of without conscious awareness.