Consider this discussion, versions of which have been played out countless times in faculty offices around the world:

Professor: Welcome. How can I help you?

Student: I am having trouble with the Solow Model. It is confusing.

Professor: Yes, this is a difficult model. What exactly is the problem?

Student: I can see how increasing the rate of population growth (n) or the depreciation rate (δ) will hurt the economy –

Professor: The nifty canonical graph, also known as the Solow diagram [which the professor quickly sketches as in Figure 3.1.1], makes that obvious, don't you think? The line rotates up and steady-state capital per worker in efficiency units falls, so steady-state output and consumption per worker in efficiency units will also fall. Ta-da!

Student: I see that for n and δ, but g is where I get really baffled. Why would technological progress hurt the economy? Shouldn't an increase in g help, with more consumption as we produce more output with the same resources?

Professor: You are forgetting that the x axis on the canonical graph is capital per worker in efficiency units. That's not the actual economy –

Student: I know that. You emphasized this point a lot in class. But here's my question then: Where is the actual economy? How can I see what is happening there? Does the canonical graph have some secret trap door that reveals the impact of g on the economy itself, not in efficiency units but in actual output per worker?

Professor: Um, no, there are no secret trap doors. The canonical graph just provides an ingenious way to find the steady-state in a model with constant technological progress. That is all it does.