The right answer depends on the collection and who it is for

The argument

A second argument offered for this position is that the question is asked at the wrong level of generality. Museums differ in ways that bear directly on the answer, proponents argue, and a rule that applies to all of them will be wrong about many. A national collection assembled with public money, holding objects the public has a claim on, is in a different position from a small institution with a specialist collection, a narrow audience and no public endowment. So is a museum in a place with heavy visitor traffic from elsewhere compared with one serving mainly its own town. The argument is that each of these differences changes the balance. Where most visitors come from elsewhere, a charge falls largely on people who do not fund the institution and who are not deterred by it, so the exclusion argument is weak and the revenue argument strong. Where visitors are mostly local and the collection is the public's own, the reverse holds. Where the collection is fragile and conservation dominates the budget, earned income matters more; where the building is underused, filling it matters more. Holders of this position argue that the mixed arrangements already in use, such as free days, free hours, free entry for residents, or a free permanent collection with charges for temporary exhibitions, exist because institutions have had to answer the question concretely rather than in principle, and have converged on mixed schemes for reasons that are good rather than merely expedient. On this account the demand for a single answer to the general question is the mistake, and what the two confident positions each offer is a correct account of some museums presented as an account of all of them.

Premises

Counter-arguments

Critics argue that this declines the question rather than answering it. Asking whether admission should be free is asking what the default ought to be, and that one institution's circumstances differ does not show there is no better default. They also argue that case by case variation has costs of its own: a public that cannot predict whether a museum is free is less likely to try, and leaving the decision to each institution tends to produce charges, since the body deciding is the one that keeps the revenue. Others note that the mixed schemes cited may reflect funding pressure rather than considered judgement.

Rejecting the premises

[Rejecting P2] Differences between institutions may shift the margin without changing which consideration is weightier, leaving a general default intact. [Rejecting P3] Convergence on mixed arrangements is at least as well explained by funding pressure and by the incentives of the body that keeps the revenue as by considered judgement. [Rejecting C] A case by case answer has costs of its own, since a public that cannot predict whether entry is free is less likely to attempt a visit at all.