The purpose of this topic is to discuss the notion "Everything that begins to exist has a cause" and it's relationship to our Universe and the implications of a finite past.
"Everything that begins to exist has a cause" is an intuitive idea, notably lacking a rigorous definition of "beginning to exist". We must take it then, to refer to the beginnings of everyday experience. In everyday experience the thing does not exist, the cause operates and then the thing exists. And, intuitively the cause is responsible for the change from the state where the object in question does not exist to a state where it does.
Now consider the case of the first moment of time. For everything that exists at that moment of time there is no prior state when it did not exist, and if a cause is needed it is not needed to bring the object into existence, for that simple reason that it already exists. Thus if we take these objects to have a beginning it is one different from the every day beginnings - and in a way that would seem to remove the need for a cause.
To save the argument then, we need a rigorous definition of "beginning to exist", we need to show that it is in fact true that everything that meets this definition has a cause - taking care to deal with the extreme cases - and we need to accept this definition when building on the argument.