Inherent vs. accidental vs. intentional difficulties in programming

It is the conventional wisdom that some aspects of programming are difficult to learn, and some aspects are error-prone even for experts. Is it possible to separate what is inherently difficult, and therefore most appropriately dealt with through education, versus what is just accidentally difficult, so a new design for a language or development environment might be able to "fix" the problem? And are there aspects that a designer makes difficult "on purpose"? For example, compare recursion, the syntax for switch statements in C, and how unification works in Prolog, respectively. It is not clear that the conventional wisdom on this topic can be trusted. For example, whereas most argue that concurrency is inherently difficult, the creators of the Alice language argue that they have found a way to make it understandable to novices. This talk will explore some HCI research on this topic, and approaches for identifying the differences.