Laws of physics arise from noticing that there are patterns in nature that appear to recur reliably. For instance, Newton's laws of motion and quantum mechanics. These suggest that the universe is not an arbitrary, eternal collection of blocks, but an emergent phenomenon that arose out of some basic principles that produce these patterns.
What would this mean in the context of a block universe? It means that there are rules governing how the could be constructed out of all the blocks. Sort of like the workings of Lego blocks and Lincoln Logs: they can only interlock in certain ways. These rules become visible to us as the patterns that we notice, and physics is the process of discovering these patterns. Perhaps if we keep investigating we might eventually be able to figure out how the blocks themselves are design and why they have these rules. This is the holy grail of physics: a "theory of everything".
But since we're part of the universe, this becomes incredibly self-referential. All our thoughts and actions are encoded in these blocks. How much sense does it make to talk about "discovering" things when the state of having this knowledge is already in the blocks? There's little room for the concepts of free will, randomness, and unpredictability.
What we view as the arrow of time is just a dimension in the block universe. The second law of thermodynamics, which says that entropy always increases in the "forward" direction of time, could be a consequence of the rules of block construction mentioned above.
How likely is it that some basic rules for interlocking blocks could produce the emergent effect of detecting and understanding the patterns produced by those rules? This is not unlike the question of how likely it is that the basic constants of physics are such that we get a stable enough universe to produce stars, planets, and life. We don't know how this happened, and a common, but not very satisfactory, solution is the anthropic principle: if things weren't the way they are, we wouldn't be here asking the question.
Doing physics essentially assumes that all these patterns really exist, and they have some cause. But it could also be an illusion, like the Matrix. Or like biblical literalists who believe that the Earth is only a few thousand years old, and that all the geographic and archeologic evidence scientists use to prove its age were created by God to make it appear older.