Invariances: The Structure of the Objective World

Filled to overflowing with ideas and insights, this book is best taken in small doses. For me, it was very hard to follow, and quickly became a chore to read, something I am unaccustomed to, since I mainly read for pleasure. It was only the exposure to Nozick's trenchant analytical prose and the chance of encountering his occasionally brilliant insights that convinced me to press on. Certainly the book will require more than one reading, with only about 70 percent comprehension the first time around. The book concerns the philosophy of science, and how the mathematical concepts relating to invariance under "all admissible transformations" can be applied to the notion of truth. The essential thesis is that objective, empirical truth is that which is invariant "under all admissible transformations". Ideas from special relativity and quantum mechanics are marshalled to support Nozick's argument that empirical truth is fundamentally relative with respect to space-time, but not relative with respect to social classes. Contemporary science is the filter through which all truths and questions about truth are passed. Though emphatically not reader-friendly, if you spend serious time with this book, you will no doubt come away with many fresh insights about the world. In summary, rewarding; but a rocky, steep climb.

Philosophy has been under severe challenge from science, literally eating up its provinces: philosophy of mind went to neuroscience; philosophy of language to Artificial Intelligence and Computer Science,etc. This book shows that there is a need for someone to just specialize in the TRUTH, its scructure, its accessibility, its INVARIANCE. Aside from the purely philosophical answers that scientists were grappling with, the book is like a manual for a new regimen in philosophy. It reviews everything from epistemology to the logic of contingency, with insights here and there about such topics as the observer biases (about computing probabilities when our existence has been linked to a particular realization of the process).I am not a philosopher but a probabilist; I found that this book just spoke to me. It certainly rid me of my prejudice against modern philosophers.

This is a fine book by an important veteran philosopher. It's Nozick's last published book before his unfortunate death.I also recommend: Williams, Truth and Truthfulness; Krausz, Relativism; Nagel, Last Word; Nozick, Philosophical Explanations; and Putnam, Realism with a Human Face; Searle, Social Construction; Searle, Rediscovery...Mind; Dummett, Logical Basis....Chapter One is on truth and relativism. Nozick situates truth in space-time and discusses objective facts (and the attractions of a correspondence theory of truth). Chapter Two extends his discussion on objective facts; he brings in the philosophy of science. Chapter Three discusses modality (necessity and contingency), and the most interesting material here is on mathematical and logical necessity (see Dummett, Putnam, and Stroud). Chapter Four is on consciousness and the mind-body problem (compare with Searle, Chalmers, and McGinn). Chapter Five is a discussion on normative ethics.I highly recommend this book. It is often quite clear and rigorous in parts.

This brilliant book is Nozick's reply to Hawking's challenge to philosophers (or those claiming to practice philosophy) today at the end of "A Brief History of Time": why is the tail of science wagging the metaphysical dog (this image is borrowed from Nozick)? Physicists today are asking the good and serious questions in philosophy by making bold hypotheses, and thereby stretching metaphysical possibilities. Meanwhile philosophers are still largely enraptured by the illusion of necessary truths and certainty in all possible worlds. The idea of objectivity as expressed by the notion of invariances is a useful and enlightening tool Nozick has provided not just for understanding better the concepts of necessity and contingency (and how similar they actually are), but how they can be used to understand the way the mind and ethics work. A must read for anyone interested in philosophy. Nozick's clarity of thought, style and wonderful sense of humour make this a highly readable work.

Any Nozick book will leave you more clever than it found you and Invariances is no exception. As Nozick more or less says in his Introduction, this book is not so much about getting the correct answers to questions, as it is about posing new and interesting questions (or, better, posing old questions in new and interesting ways). The value here is that thinking about the world in news ways puts our current ideas in jeopardy (which is a good thing) and forces those ideas to step up to bat in order to remain our current ideas.Invariances will make some ideas which you may have dismissed as foolish seem plausible (even though you'll still probably dismiss them) and force you to confront some new thoughts in epistemology, philosophy of science, and ethics. Nozick is an antidote to the not fully explored idea. What you don't know might hurt you, but what you half-know will.