Causation

Causation has been a topic discussed from as early as anyone can remember. From Aristotle, through Aquinas and right the way to Hume, Lane-Craig and many others. The question I would like to propose to the good people of this forum is: is an infinite chain of causes possible?

Things in our universe are caused. These things are often caused by someone else. As the classical deterministic argument goes, we can analyze what we do, and we can trace back the previous events and causes that have occurred in our life that would eventually lead us to make a certain decision. Since all we do is determined by previous causes, we cannot have free will. I do not intend discussing the plausibility of the argument, nor of the nature of free will.

Rather, could this series or chain of causes that made us perform an action be infinite? Or, must they be finite? It seems problematic to suggest that there can be an infinite amount of causes, and then a last cause. But, on the other hand, one could look at it differently. A one-side bounded infinity seems entirely possible. For example: the amount of positive integers. They have a definite beginning: 1. But, they potentially extend into +oo. So, it may well be proposed that there can be a last cause, and then an infinite chain of causes that extend endlessly and infinitely into the past.

Is such a thing possible? Is the conception of a last cause and an infinite chain of causes mutually exclusive? Thoughts would be greatly appreciated.