arguments to displace Aristotle's physics, proposing that bodies all fall at the same speed whatever their weight. On 18th/19th-century thinkers The 19th-century German philosopher Friedrich Nietzsche has been said to have taken nearly all of his political philosophy from Aristotle. Aristotle rigidly separated action from production, and argued for the deserved subservience of some people ("natural slaves"), and the natural superiority (virtue, arete) of others. It was Martin Heidegger, not Nietzsche, who elaborated a new interpretation of Aristotle, intended to warrant his deconstruction of scholastic and philosophical tradition. The English mathematician George Boole fully accepted Aristotle's logic, but decided "to go under, over, and beyond" it with his system of algebraic logic in his 1854 book The Laws of Thought. This gives logic a mathematical foundation with equations, enables it to solve equations as well as check validity, and allows it to handle a wider class of problems by expanding propositions of any number of terms, not just two. Charles Darwin regarded Aristotle as the most important contributor to the subject of biology. In an 1882 letter he wrote that "Linnaeus and Cuvier have been my two gods, though in very different ways, but they were mere schoolboys to old Aristotle". Also, in later editions of the book "On the Origin of Species', Darwin traced evolutionary ideas as far back as Aristotle; the text he cites is a summary by Aristotle of the ideas of the earlier Greek philosopher Empedocles. James Joyce's favoured philosopher was Aristotle, whom he considered to be "the greatest thinker of all times". Samuel Taylor Coleridge said: Everybody is born either a Platonist or an Aristotelian. Ayn Rand acknowledged Aristotle as her greatest influence and remarked that in the history of philosophy she could only recommend "three A's"—Aristotle, Aquinas, and Ayn Rand. She also regarded Aristotle as the greatest of all philosophers. Karl Marx considered Aristotle to be the "greatest thinker of antiquity", and called him a "giant thinker", a "genius", and "the great scholar". Modern rejection and rehabilitation During the 20th century, Aristotle's work was widely criticized. The philosopher Bertrand Russell argued that "almost every serious intellectual advance has had to begin with an attack on some Aristotelian doctrine". Russell called Aristotle's ethics "repulsive", and labelled his logic "as definitely antiquated as Ptolemaic astronomy". Russell stated that these errors made it difficult to do historical justice to Aristotle, until one remembered what an advance he