Damian Hinds' proposal that universities should perhaps be forced to charge different amounts for different courses, depending on their utility to the student, their utility to the nation, and their cost to deliver, may open a can of worms.
Because it is almost impossible at any time to predict which courses will deliver the greatest personal and national monetary rewards - and even more so today, when so many of our skilled jobs are at risk of being taken by robots.
Also, should a course that costs a university almost nothing to provide, but which has a weak correlation with any high-earning careers, have a high or low fee for the student attached to it?
And anyway, have we reached an impasse where we value a university education only for how it will enrich us in a material sense, and place no value on cultural or spiritual enrichment?
Politically, too, differential pricing for degrees is a risky idea for the Tories.
Because it concedes to Labour that there is a benefit to the whole country from young people going to university - which is Labour’s most respectable argument for wanting to abolish university fees and fund all higher education from general taxation.
As it happens, Justine Greening was elbowed by the Prime Minister out of the education department a few weeks ago because she could not be persuaded that cutting what students pay was politically or economically sensible.
She sees - rightly - that cutting fees and the associated student debts, or the rate of interest on those debts, is a windfall to the richest students and families; it is regressive.
So, on Peston on Sunday she mapped out the policy she had been developing during her time as secretary of state and is still urging - namely that students should no longer borrow to pay fees, but should simply pay a flat nine percent a year on all earnings over an income threshold (which would be £25,000) for a time-limited period.
Obviously that looks and quacks like a graduate tax - though Greening would like it to be seen as a contribution to a special higher education fund, into which employers could also be spurred to make payments.
Importantly it would be universal for all graduates; unlike today’s system, rich students could not repay what they owe before the end of the fixed term.
Greening would argue that this would keep the equity in the current system, that those who don’t go to university aren’t being asked to make big subsidies to this who do.
And it would eliminate the putative stigma and deterrent for poorer young people of accumulating huge debts to better themselves.
It is an argument that might woo a few voters, who don’t believe that the best use of scarce resources is to pay for teenagers from wealthy households to go to university, rather than hiring more teachers and nurses: for the Tories it could be potentially effective against Corbyn’s bribe to young people.
Although in dumping Greening, May has presumably dumped her ideas.
By contrast it is not clear that pricing a degree in ancient Greek more or less than one in robotics will move the public-opinion dial even by a nano metre.