The text under review is an extremely important synthesis of the contemporary discussions of one of the hardest questions faced by science and philosophy throughout the centuries, a real intellectual crux, namely the relationship between mind and matter. To illuminate the problem Redner uses the much debated – and sometimes abused – concept of emergence.

He clearly has a solid command of the relevant literature on the subject, which he expounds with clarity and criticises with a penetrating as well as impartial eye (perhaps the only exception to this impartiality may be found in his critique of the corpus of theories which he wittily dubs “MIT-Mind”, an irony, by the way, that I, myself, can’t afford not to share). This command of modern literature is admirably complemented by his apt and frequent recourse to the classics, especially Spinoza.

The text is well structured around the brilliant literary figure of the Shakespearian citation introduced from the very beginning in the title. Its function is not merely a metaphorical but a substantive one, and is consistently applied to the schema of five levels of emergence, in parallel with the old Aristotelian model of the five elements echoed in the words of Hamlet.

All this amounts to saying that I find the core of the argument, as well as its exposition, coherent, convincing and illuminating. There are only, in my opinion, two critical observations that could be made to the argument, from the philosophical – not necessarily scientific – point of view.

The first, and most important one, is what I would call a certain “Humean” bias in the contraposition of causality to emergence. To say, as Redner seems to do, that the relationship between “emerger” and “emergent” is a necessary, even a “logical” one, while that existing between cause and effect is “contingently empirical”, seems to me an excess, surely prompted by Redner’s “zeal” in his defence of the explanatory power of emergence. It is one thing to say, following Hume, that the relationship between cause and effect is not a logical or “analytical” one, and another to say that what Galen calls “the secret connection” (causality) is in no way guaranteed by rational inference, due to a “lag” or “gap”  between antecedent and consequent. But in order to avoid the absurd admission of “holes” (certainly “black” ones) or discontinuities in the natural processes, we have to postulate continuity between cause and effect, which amounts to recognising a necessary “superposition” of cause and effect in the very moment of causation.

My second, more marginal, observation is that Redner – having well established in his text the two essential properties of emergence, i.e. non-separability and non-identity of emerger and emergent – could, for the benefit of his argument, have dwelled more at length on countering some of the objections that used to be raised against the very concept of emergence. To mention only one of them, I’m thinking of what Thomas Nagel has to say incidentally about emergence in chapter 13 of his well-known book Mortal Questions. Nagel’s critique sounds very like the idea that emergence, if too radically understood as an absolute, qualitatively unpredictable innovation (i.e. unforeseeable a priori on the basis of the mere initial properties of the “emerger”) could be easily confused with some kind of “ex nihilo” creation, or viewed as a violation of the apparently reasonable principle that “effect cannot be ontologically superior to its cause.” Perhaps a reminder of the old Aristotelian concept of dynamis as opposed to entelechia could be of some help here.

The preceding observations in no way diminish the value of this work, its utility for scholars, researchers, graduate and even undergraduate students, in order to dispel some of the dangerous incantations derived from the impoverishing, reductionist approach reigning in many of the scientific disciplines concerned with the subject, all of which Redner aptly characterizes. This is to say that I put Quintessence of Dust in the top 5% of books in the field.    

Miguel Candel Sanmartin is a Spanish philosopher and translator, who taught ancient philosophy, Greek and the history of ancient and medieval philosophy at the University of Barcelona, where he was Director of the Department of History of Philosophy, Aesthetics and Philosophy of Culture, and is now Professor Emeritus. He is an authority on Aristotelian logic and metaphysics and its influence on modern philosophy and has also translated works by Hannah Arendt and Alfred North Whitehead. He is the author of Aristotle: Treatises on Logic: Complete Works (Gredos, 1982, 1986), and the three volume edition, Aristotle: Obra Completa (Gredos, 2011). He recently completed a research project, entitled: “The Aristotelian Gnoseological Tradition and the Origins of the Philosophy of Mind”, 2013-2016, funded by the Spanish Ministry of Economy and Competitiveness.