It is clear that the world had no beginning, since if it did, there would have been a first moment before which there was no other moment, but every moment is preceded by some previous moment. At times when arguments are offered in ordinary discourse, premise or conclusion indicators are not used. When this happens, identifying the conclusion requires that we determine the statement in the argument that the author of the argument is trying to support. It can be helpful to make the structure of an argument explicit when writing it out. When this is done, the convention in logic is to write out each premise as a separate statement, often numbered or lettered, followed by the conclusion.
Every moment is preceded by some previous moment.
The world had no beginning. Notice that when we put the argument in this form, the premise and conclusion indicators can be removed. Other conventions apply in some forms of logic that determine the order in which the premises are written, but we will not consider these conventions here. At times in this course we will express arguments in this conventional form to make the logical relationship between the premises and the conclusion clear. The deductive standards are called validity and soundness .