Donald Mackinnon’s The Problem of Metaphysics (Cambridge University Press, 1974), which is the revised version of his Gifford lectures delivered at the University of Edinburgh in the springs of 1965 and 1966, might be suspected by its readers to be deceptively titled. Though beginning with an overview of Kant’s and Aristotle’s ‘descriptive metaphysics’ (as opposed to ‘revisionary’–Mackinnon takes the distinction from P.F. Strawson), as the lectures range over ethics, parables, tragedy and transcendence, it becomes evident that the horizon of Mackinnon’s inquiry stretches well beyond the disciplinary boundaries of academic philosophy. Mackinnon spends little time addressing the remit of the Gifford Trust directly, but the problem of which he speaks is implicitly that of any enterprise claiming to be natural theology: inquiring by means of natural senses and concepts into something that is expected to be beyond sense and is likely inconceivable. Metaphysics is a problem in this sense. It is an enterprise that, even in its strictly descriptive mode, must in the end admit that those features of the world it aims to document remain elusive to definite description by virtue of their foundational nature.
Metaphysics thought of in this way is for Mackinnon one especially powerful mode of inquiry into what can be broadly called the absolute or transcendent. The transcendent is on Mackinnon’s terms something with which metaphysics must always grapple, and also brings metaphysics very close to the existential. His guides, principally Kant and Aristotle, but also Plato, all agree (though the details differ vastly) about the significance of the absolute to any claims made about ontology, but also find that this kind of realism about the absolute has as much moral consequence as it does ontological. The reverse is also true; any serious moral inquiry requires, eventually, making claims about how the world is.
It is this that that Mackinnon circles around from different vantage points throughout his essay: the mutually informing, mutually dependent arenas of metaphysics and morals (readers of Iris Murdoch, one of Mackinnon’s most famous students, will no doubt find much of interest in this volume). Those non-discursive discourses, such as parable and tragedy, which are prominent in the study, serve to underline not only the elusive nature of the object upon which metaphysics tries to gain conceptual purchase, but also the convergence between what is formally rigorous and abstract with the stuff of moral action and mutual good.
Why then does Mackinnon take metaphysicians as his principle interlocutors, instead of poets or playwrights? One suspects there are some circumstantial factors: Mackinnon composed the Giffords when A.J. Ayer’s positivism was still a powerful, if waning force in British philosophy, and it is clear Mackinnon finds such philosophy wanting. Yet any polemics would have been secondary. He was convinced of two things: first, that metaphysical realism offers an objective, conceptually articulated defence against a morally injurious anthropomorphism of reality, and second, that kind of conceptual discourse such metaphysics could provide was a necessary part of the broader moral and indeed spiritual investigation of that reality.
Mackinnon was apparently a singular figure and this is a singular volume. While capacious in its frame of reference, it is never baggy, and is always driven by a restless but focused energy.