Two contrasting reflections by Aristotle which cover very particular ground. In 'On the Soul', Aristotle presents his view of the 'life essence' which, he argues, is possessed by living things whether plants, animals or humans. Not a 'soul' in the generally accepted Western use of the term, this 'soul', he says, is a life force that is indivisible from the organism that possesses it.

John Locke and his works - particularly An Essay Concerning Human Understanding - are regularly and rightly presented as foundations for the Age of Enlightenment. His primary epistemological message - that the mind at birth is a blank sheet waiting to be filled by the experiences of the senses - complemented his primary political message: that human beings are free and equal and have the right to envision, create and direct the governments that rule them and the societies within which they live.

The Problems of Philosophy discusses Bertrand Russell's views on philosophy and the problems that arise in the field. Russell's views focus on knowledge rather than the metaphysical realm of philosophy. The Problems with Philosophy revolves around the central question that Russell asks in his opening line of Chapter 1 - Is there any knowledge in the world which is so certain that no reasonable man could doubt it?

There is a cause, or a reason, behind everything that happens. This is the fundamental view behind the classical proposition the Principle of Sufficient Reason, which, in 1813, Schopenhauer chose as his subject for further examination in his doctoral dissertation On the Fourfold Root of the Principle of Sufficient Reason....

One of the most influential philosophers and theologians in the history of Western thought, St Thomas Aquinas established the foundations for much of modern philosophy of religion, and is famous for his arguments for the existence of God. In this cogent and multifaceted introduction to the great saint's work, Edward Feser argues that you cannot fully understand Aquinas' philosophy without his theology, and vice-versa. He covers Aquinas' thoughts on the soul, natural law, metaphysics, and more.

The Tractatus Logico-Philosophicus (Logical Philosophical Treatise or Treatise on Logic and Philosophy) is the only full-length philosophical book by the Austrian philosopher Ludwig Wittgenstein that was published during his lifetime. The goal of the work is to identify the relationship between language and reality and to define the limits of science. He famously summarized the book in the following way: "What can be said at all can be said clearly; and what we cannot talk about we must pass over in silence."

Logic is synonymous with reason, judgment, sense, wisdom, and sanity. Being logical is the ability to create concise and reasoned arguments - arguments that build from given premises, using evidence, to a genuine conclusion. But mastering logical thinking also requires studying and understanding illogical thinking, both to sharpen one's own skills and to protect against incoherent or deliberately misleading reasoning. Elegant, pithy, and precise, Being Logical breaks logic down to its essentials through clear analysis, accessible examples, and focused insights.

Written in 1917, The Law and the Word is a hard-to-find work by Judge Thomas Troward, a pioneer in mental science. Troward's writings and lectures greatly influenced Ernest Holmes, the founder of Religious Science and writer of The Science of Mind.

This book was one of the first to combine thought energy, scientific reasoning and testing, and creative power, and to see the interconnection of the three.

First published in 1859, John Stuart Mill's On Liberty is an exhaustive exploration of social and civic liberty, its limits, and its consequences. Mill's work is a classic of political liberalism that contains a rational justification of the freedom of the individual in opposition to the claims of the state.

A dialogue between Socrates and Meno probes the subject of ethics. Can goodness be taught? If it can, then we should be able to find teachers capable of instructing others about what is good and bad, right and wrong, or just and unjust.

The Summa Theologica, by Thomas Aquinas, is a fundamental text in Catholic doctrine, a compendium of theology that has been studied and debated since its first publication in the 13th century. Furthermore, it has been widely regarded as one of the classics of Western philosophy, not least because, perhaps for the first time in such a systematic manner, it set out to consider the views of non-Christian figures such as Aristotle, Boethius, Muslim writers including Averroes (Ibn Rushd) and Avicenna (Ibn Sina) and the Sephardic Jewish scholar Maimonides.

Considered by many to be Hannah Arendt's greatest work, published as she neared the end of her life, The Life of the Mind investigates thought itself, as it exists in contemplative life. In a shift from her previous writings, most of which focus on the world outside the mind, this work was planned as three volumes that would explore the activities of the mind considered by Arendt to be fundamental. What emerged is a rich, challenging analysis of human mental activity, considered in terms of thinking, willing, and judging.

This scientific writing, which was considered to be the groundwork of evolutionary biology, presented the theory that species developed over a line of originations through a method of natural selection. It imparted evidence that the variety of life resulted from a common descent via a branching model of evolution.

The Origin of Species sold out on the first day of its publication in 1859. It is the major book of the 19th century and one of the most readable and accessible of the great revolutionary works of the scientific imagination. Though, in fact, little read, most people know what it says—at least they think they do. The Origin of Species was the first mature and persuasive work to explain how species change through the process of natural selection. Upon its publication, the book began to transform attitudes about society and religion.

What does it mean to be truthful? What role does truth play in our lives? What do we lose if we reject truthfulness? No philosopher is better suited to answer these questions than Bernard Williams. Writing with his characteristic combinationof passion and elegant simplicity, he explores the value of truth and finds it to be both less and more than we might imagine.