Satoshi both rolls the dice and doesn't roll the dice: In the creation of the longest chain approximately every 10 minutes, this is deterministic when analyzed on a global, overall level: Satoshi doesn't roll the dice, as someone will always manage to generate the longest chain in roughly the same time. However, during the process of generating the time chain, who creates the latest chain is uncertain. Any competitor has a probabilistic chance of generating the latest time chain. When analyzed on a collective level: Satoshi rolls the dice, and it's uncertain who will produce the longest chain.