u/Ok-Policy-1084

I’m currently studying Aquinas’ cosmological arguments for my course. Upon reading some critics for Aquinas’ second way ( argument for causation ), I’ve stumbled upon Hume’s critique regarding causation. What I’m failing to grasp is the idea that it is logically possible that some things happen without a cause. I’m just not sure how this makes sense. If anyone could help it would be much appreciated.