1. What the point of Hoare's approach?

He's trying to ensure that programs run correctly and meet their intended
requirements by proving that they're correct. Their behavior is described by
logical axioms in addition to the code, and proofs of correctness could be built
using the axioms.


2. More likely on languages of the era or now?

Much more likely then.  We now have exceptions, parallelism and concurrency,
etc, that make it much harder to reason about the behavior of our programs.


3. Does Backus think we need new languages, architectures, or both?

He's primarily concerned about languages, but thinks that sticking with von
Neumann has constrained our choices for languages and that different
architectures might help support better languages.

"Although the conditions that produced its architecture have changed radically,
we nevertheless still identify the notion of "computer" with this thirty year
old concept. [...] Surely there must be a less primitive way of making big
changes in the store than by pushing vast numbers of words back and forth
through the von Neumann bottleneck."

"Our thirty year old belief that there is only one kind of computer is the basis
of our belief that there is only one kind of programming language"


4. What does Backus think of Hoare's approach?

"If the average programmer is to prove his programs correct, he will need much
simpler techniques than those the professionals have so far put forward."