Martin Cohen is a teacher and writer specializing in philosophy, ethics and education, with a special interest in computing. His books include 101 Philosophy Problems (2nd edn., 2001), Political Philosophy (2001) and 101 Ethical Dilemmas (2003). He has been editor of The Philosopher since 1995.

"Martin Cohen's book is a delight to the intellect. His discussion of historically important thought experiments displays considerable erudition, permeated by wit and occasionally farcical invention which embellish the philosophical value of his treatment."Zenon Stavrinides, University of Bradford "Cohen's book is packed with wit and scurrilous remarks about mainstream philosophers. His inimitable writing style, which entertains as it instructs, is directed towards making philosophical ideas immediately accessible to the general reader."George MacDonald Ross, University of Leeds "One of the fun things about philosophy is that you can sit back in your armchair, set up a laboratory in your own head and calmly observe the results of mixing x with y. This is the grand tradition of the "thought experiment", to which Cohen provides a zippy alphabetical guide. Cohen's explanations of the problems are lucid, and he defends the tradition against killjoys who argue that thought experiments cannot ever give reliable conclusions. At its best the thought experiment can be a highly compressed, conceptually fruitful marriage of science and literature."Steven Poole on Wittgenstein's BeetleSaturday November 20, 2004The Guardian "The value of this little book is that it collects a wide range of thought experiments and presents them in an accessible way. It is a good place to start, and it will be especially useful for those who teach courses on the topic and want to introduce it to a new generation of students."James Robert Brown, University of Toronto "There are several books of philosophical thought experiments currently in print... Cohen's A-Z are mostly of historic significance to science. They are wittily presented..."Times Literary Supplement

• List of Figures viiForward! viiiIntroduction: Deep Thought – a brief history of thought experiments 1The A–ZA is for Alice and Astronomers Arguing about Acceleration 15B is for Bernard’s Body-Exchange Machine 18C is for the Catholic Cannibal 20D is for Maxwell’s Demon 25E is for Evolution (and an Embarrassing Problem with it) 28F is for the Forms Lost Forever to the Prisoners of the Cave 30G is for Galileo’s Gravitational Balls 33H is for Hume’s Shades 37I is for the Identity of Indiscernibles 41J is for Henri Poincaré and Alternative Geometries 45K is for the Kritik and Kant’s Kind of Thought Experiments 48L is for Lucretius’ Spear 52M is for Mach’s Motionless Chain 55N is for Newton’s Bucket 58O is for Olbers’ Paradox 62P is for Parfit’s Person 65Q is for the Questions Raised by Thought Experiments Quotidiennes 67R is for the Rule-Ruled Room 70S is for Salvatius’ Ship, Sailing along its own Space-Time Line 74T is for the Time-Travelling Twins 78U is for the Universe, and Einstein’s Attempts to Understand it 81V is for the Vexed Case of the Violinist 84W is for Wittgenstein’s Beetle 87X is for Xenophanes and Thinking by Examples 90Y is for Counterfactuals and a Backwards Approach toHistory 93Z is for Zeno and the Mysteries of Infinity 97Notes for ExperimentersHow to Experiment 103Notes and Cuttings 117Who’s Who of Experimenting 126Acknowledgements 131Index 132

Martin Cohen is a teacher and writer specializing in philosophy, ethics and education, with a special interest in computing. His books include 101 Philosophy Problems (2nd edn., 2001), Political Philosophy (2001) and 101 Ethical Dilemmas (2003). He has been editor of The Philosopher since 1995.

"Martin Cohen's book is a delight to the intellect. His discussion of historically important thought experiments displays considerable erudition, permeated by wit and occasionally farcical invention which embellish the philosophical value of his treatment."Zenon Stavrinides, University of Bradford "Cohen's book is packed with wit and scurrilous remarks about mainstream philosophers. His inimitable writing style, which entertains as it instructs, is directed towards making philosophical ideas immediately accessible to the general reader."George MacDonald Ross, University of Leeds "One of the fun things about philosophy is that you can sit back in your armchair, set up a laboratory in your own head and calmly observe the results of mixing x with y. This is the grand tradition of the "thought experiment", to which Cohen provides a zippy alphabetical guide. Cohen's explanations of the problems are lucid, and he defends the tradition against killjoys who argue that thought experiments cannot ever give reliable conclusions. At its best the thought experiment can be a highly compressed, conceptually fruitful marriage of science and literature."Steven Poole on Wittgenstein's BeetleSaturday November 20, 2004The Guardian "The value of this little book is that it collects a wide range of thought experiments and presents them in an accessible way. It is a good place to start, and it will be especially useful for those who teach courses on the topic and want to introduce it to a new generation of students."James Robert Brown, University of Toronto "There are several books of philosophical thought experiments currently in print... Cohen's A-Z are mostly of historic significance to science. They are wittily presented..."Times Literary Supplement

• List of Figures viiForward! viiiIntroduction: Deep Thought – a brief history of thought experiments 1The A–ZA is for Alice and Astronomers Arguing about Acceleration 15B is for Bernard’s Body-Exchange Machine 18C is for the Catholic Cannibal 20D is for Maxwell’s Demon 25E is for Evolution (and an Embarrassing Problem with it) 28F is for the Forms Lost Forever to the Prisoners of the Cave 30G is for Galileo’s Gravitational Balls 33H is for Hume’s Shades 37I is for the Identity of Indiscernibles 41J is for Henri Poincaré and Alternative Geometries 45K is for the Kritik and Kant’s Kind of Thought Experiments 48L is for Lucretius’ Spear 52M is for Mach’s Motionless Chain 55N is for Newton’s Bucket 58O is for Olbers’ Paradox 62P is for Parfit’s Person 65Q is for the Questions Raised by Thought Experiments Quotidiennes 67R is for the Rule-Ruled Room 70S is for Salvatius’ Ship, Sailing along its own Space-Time Line 74T is for the Time-Travelling Twins 78U is for the Universe, and Einstein’s Attempts to Understand it 81V is for the Vexed Case of the Violinist 84W is for Wittgenstein’s Beetle 87X is for Xenophanes and Thinking by Examples 90Y is for Counterfactuals and a Backwards Approach toHistory 93Z is for Zeno and the Mysteries of Infinity 97Notes for ExperimentersHow to Experiment 103Notes and Cuttings 117Who’s Who of Experimenting 126Acknowledgements 131Index 132

Martin Cohen is a teacher and writer specializing in philosophy, ethics and education, with a special interest in computing. His books include 101 Philosophy Problems (2nd edn., 2001), Political Philosophy (2001) and 101 Ethical Dilemmas (2003). He has been editor of The Philosopher since 1995.

"Martin Cohen's book is a delight to the intellect. His discussion of historically important thought experiments displays considerable erudition, permeated by wit and occasionally farcical invention which embellish the philosophical value of his treatment."Zenon Stavrinides, University of Bradford "Cohen's book is packed with wit and scurrilous remarks about mainstream philosophers. His inimitable writing style, which entertains as it instructs, is directed towards making philosophical ideas immediately accessible to the general reader."George MacDonald Ross, University of Leeds "One of the fun things about philosophy is that you can sit back in your armchair, set up a laboratory in your own head and calmly observe the results of mixing x with y. This is the grand tradition of the "thought experiment", to which Cohen provides a zippy alphabetical guide. Cohen's explanations of the problems are lucid, and he defends the tradition against killjoys who argue that thought experiments cannot ever give reliable conclusions. At its best the thought experiment can be a highly compressed, conceptually fruitful marriage of science and literature."Steven Poole on Wittgenstein's BeetleSaturday November 20, 2004The Guardian "The value of this little book is that it collects a wide range of thought experiments and presents them in an accessible way. It is a good place to start, and it will be especially useful for those who teach courses on the topic and want to introduce it to a new generation of students."James Robert Brown, University of Toronto "There are several books of philosophical thought experiments currently in print... Cohen's A-Z are mostly of historic significance to science. They are wittily presented..."Times Literary Supplement

• List of Figures viiForward! viiiIntroduction: Deep Thought – a brief history of thought experiments 1The A–ZA is for Alice and Astronomers Arguing about Acceleration 15B is for Bernard’s Body-Exchange Machine 18C is for the Catholic Cannibal 20D is for Maxwell’s Demon 25E is for Evolution (and an Embarrassing Problem with it) 28F is for the Forms Lost Forever to the Prisoners of the Cave 30G is for Galileo’s Gravitational Balls 33H is for Hume’s Shades 37I is for the Identity of Indiscernibles 41J is for Henri Poincaré and Alternative Geometries 45K is for the Kritik and Kant’s Kind of Thought Experiments 48L is for Lucretius’ Spear 52M is for Mach’s Motionless Chain 55N is for Newton’s Bucket 58O is for Olbers’ Paradox 62P is for Parfit’s Person 65Q is for the Questions Raised by Thought Experiments Quotidiennes 67R is for the Rule-Ruled Room 70S is for Salvatius’ Ship, Sailing along its own Space-Time Line 74T is for the Time-Travelling Twins 78U is for the Universe, and Einstein’s Attempts to Understand it 81V is for the Vexed Case of the Violinist 84W is for Wittgenstein’s Beetle 87X is for Xenophanes and Thinking by Examples 90Y is for Counterfactuals and a Backwards Approach toHistory 93Z is for Zeno and the Mysteries of Infinity 97Notes for ExperimentersHow to Experiment 103Notes and Cuttings 117Who’s Who of Experimenting 126Acknowledgements 131Index 132