Reasoning about God (New York: Routledge, 2023), 180 pages: a text on philosophy of religion for beginning to intermediate undergraduates. Order it from Amazon or Routledge. Click here for a fuller explanation of this book.

Ethics: A Contemporary Introduction, third edition (New York: Routledge, 2018), 254 pages, with the companion EthiCola instructional program and Teacher Manual: a text for beginning to intermediate undergraduates, with a heavy emphasis on the golden rule. This is a thorough rewrite of earlier editions; click here for improvements. Order it from Amazon or Routledge. Mehdi Akhavan is translating this book into Persian.

Great Catholic Philosophers (2017) is a series of audio 24 talks, professionally recorded by Learn25 (formerly Now You Know Media); it's also available in an Audible Audiobook format. The talks are on BEGINNINGS (Introduction; Bible, Plato, & Aristotle; Aristides, Justin, Clement, & Tertullian; Irenaeus clarifies the problem of evil; Menucius Felix debates non-believers; Origen criticizes biblical fundamentalism; Augustine converts to Christianity; Augustine on Christian doctrine); MIDDLE (Middle Ages through Anselm; Arguments for God's existence; Aquinas on faith & reason; Aquinas on God as first cause; Aquinas on God as the world's designer; Aquinas & the natural moral law; Ockham, Loyola, & Galileo; Descartes); and RECENT (Catholic philosophy in transition, Loss of faith among intellectuals, Teilhard & evolution, Stein on woman's special value, Callahan on pro-life feminism, Copleston debates Russell, Plantinga on Christian philosophy, Rescher & John Paul II). These talks are based on my Anthology of Catholic Philosophy.

Introduction to Logic, third edition (New York: Routledge, 2017), 414 pages, with the companion LogiCola instructional program and Teacher Manual: a basic and intermediate logic text. This is a thorough rewrite of the second edition; my preface to the third edition talks about improvements. Yuping Shen 沈榆平, Xuefeng Wen 文学锋等, et al. translated this third edition into Chinese as 逻辑学导论 click here (Beijing 北京: Science Press 科学出版社, 2021). Kyung Mun Sa Publishing is translating this book into Korean. Click here or here to order.

Ethics and Religion (New York: Cambridge University Press, 2016), 196 pages. This book develops strong versions of both divine command theory (which sees God's will as creating the moral order) and natural law (which accepts ethical truths that don't depend on God's will but perhaps depend on his reason or creation). It also deals with how atheists object on ethical grounds to belief in God and how they view ethics; it defends belief from their objections. It also explores related topics, such as practical reason, the golden rule, ethics and evolution, the problem of evil, and the fine-tuning argument. Click here to order. Raaad Zamil translated it into Arabic as الأخلاق والدین (Beiruit: Dar al-Rafidain, 2017).

The Golden Rule: A Moral Ideal for the World (2013) is a series of 12 talks, professionally recorded by Learn25 (formerly Now You Know Media) in video and audio versions; it's also available in an Audible Audiobook format. The talks are on BASICS (Introduction, Fallacies, Stories); PRACTICE (Moral education, Egoism and evolution, Applied ethics); RELIGION (Christianity, Interfaith dialogue, Non-Christian faiths); and HISTORY (Before 1900 - this one is online as a sample, The slavery debate, Since 1900). These talks are based on my Ethics and the Golden Rule.

Ethics and the Golden Rule (New York: Routledge, 2013), a fairly comprehensive treatment of the golden rule ("Treat others as you want to be treated"). It covers a wide range of topics, such as how the golden rule connects with world religions and history, how it applies to practical areas like moral education and business, and how it can be understood and defended philosophically. I wrote this to be a "golden-rule book for everyone," from students to general readers to specialists. Click here for a video overview or here to preview the first 30 pages. Click here to order (or click here for the Kindle version, which I fine-tuned to fit the e-book format). Mehdi Akhavan is translating this book into Persian.

Ethics: A Contemporary Introduction, second edition (New York: Routledge, 2011), 190 pages, with the companion EthiCola instructional program and Teacher Manual: a text for beginning undergraduates. This book is obsolete, replaced by a third edition.

Introduction to Logic, second edition (New York: Routledge, 2010), 420 pages, with the companion LogiCola instructional program and Teacher Manual: a basic and intermediate logic text. This is a thorough rewrite of the first edition, with added chapters on the history of logic, deviant logic, and philosophy of logic. Translated into Portuguese as Introdução à Lógica by Christian Marcel de Amorim Perret Gentil Dit Maillard (São Paulo: Paulus, 2016, buy on Amazon). This book is obsolete, replaced by a third edition.

Historical Dictionary of Ethics (Lanham, Md., Scarecrow Press [Rowman & Littlefield], 2008), 363 pages, a one-volume encyclopedia of ethics, co-authored with Earl W. Spurgin. The A to Z of Ethics (2010) is a paperback version. Mehdi Akhavan and Seyyed Mohsen Eslami have translated the book into Persian as فرهنگ تاریخی فلسفه اخلاق, and it is now in the publishing process.

Historical Dictionary of Logic (Lanham, Md., Scarecrow Press [Rowman & Littlefield], 2006), 307 pages, a one-volume encyclopedia of logic. The A to Z of Logic (2010) is a paperback version.

The Sheed & Ward Anthology of Catholic Philosophy (Lanham, Md.: Rowman & Littlefield, 2005), 585 pages: a text and source book, co-edited with James C. Swindal.

Ethics: Contemporary Readings (New York: Routledge, 2004), 314 pages: an ethics anthology, co-edited with Earl W. Spurgin and James C. Swindal.

Introduction to Logic, first edition (New York: Routledge, 2002), 399 pages, with the companion LogiCola instructional program and Teacher Manual: a basic and intermediate logic text. This is a thorough rewrite of the two Prentice-Hall logic books mentioned below, incorporating and updating all of their materials. Chapter 11 was translated into Persian by Mehdi Akhavan and published in the Iranian journal Naqd o Nazar. This book is obsolete, replaced by a third edition.

Ethics: A Contemporary Introduction, first edition (New York: Routledge, 1998), 211 pages, with the companion EthiCola instructional program and Teacher Manual: a text for beginning undergraduates. Translated into Chinese as 倫理 by Zhoubaheng Danshile (Taiwan: Weber, 1999), into French as Questions d'éthique: Une approche raisonnée de quelques perspectives contemporaines by M.-C. Désorcy (Montréal and Toronto: Chenelière/McGraw-Hill, 2002), into Thai as จริยศาสตร์ร่วมสมัยเบื้องต้น by Jakaew Tanunath (Bangkok, 2006), and into Persian as درآمدی بر فلسفه اخلاق معاصر by Mehdi Akhavan (Tehran: Elmi-Farhangi, 2009) and reprinted in 2020. Three selections translated into a Portuguese reader, A Arte de Pensar, ed. Desidério Murcho (Lisbon: Didáctica Editora, 2007). This book is obsolete, replaced by a third edition.

Formal Ethics (New York: Routledge, 1996), 213 pages, with the companion EthiCola instructional program: a scholarly work on the golden rule and related principles. Translated into Persian as اخلاق صوری by Mehdi Akhavan (Tehran, Iran: Elmi-Farhangi, 2009).

Symbolic Logic: Classical and Advanced Systems (Englewood Cliffs: Prentice Hall, 1990), 329 pages, with the companion LogiCola instructional program and Teacher Manual: an intermediate logic text. This book is now out of print and obsolete, replaced by my Introduction to Logic (above).

Logic: Analyzing and Appraising Arguments (Englewood Cliffs: Prentice Hall, 1989), 438 pages, with the companion LogiCola instructional program and Teacher Manual and Study Guide: a basic logic text. This book is now out of print and obsolete, replaced by my Introduction to Logic (above).

Gödel's Theorem Simplified (Washington: University Press of America, 1984), 83 pages: a simpler presentation of the theorem.

To order any of my books, click here or here. Several of my books are available in e-book format: Kindle, Sony, Routledge (search for author Gensler).

Some of my articles are available online (but some may be accessible only from university locations):

• "A simplified decision procedure for categorical syllogisms," Notre Dame Journal of Formal Logic 14 (1973): 457-66.
• "The prescriptivism incompleteness theorem," Mind 85 (1976): 589-96.
• "Acting commits one to ethical beliefs," Analysis 43 (1983): 40-43.
• "How incomplete is prescriptivism?" Mind 93 (1984): 103-107.
• "Logic and the first critique," Kant-Studien 76 (1985): 276-87.
• "Ethical consistency principles," The Philosophical Quarterly 35 (1985): 156-70.
• "A Kantian argument against abortion," Philosophical Studies 48 (1985): 57-72 and 49 (1986): 83-98.
• "Ethics is based on rationality," Journal of Value Inquiry 20 (1986): 251-64.
• "A click in the right direction: Marry textbooks and computers and you may have a learning match made in heaven," London Times Higher Education Supplement (textbook guide, February 26, 1999): page 9.
• I had a debate with Peter Singer at John Carroll University on December 4, 2000 about the sanctity of human life. Here's the text of my response to Singer. For an expanded version of the debate, see my "Singer's unsanctity of human life: A critique," in Peter Singer Under Fire, edited by Jeffrey A. Schaler (Chicago: Open Court, 2009), pages 163-84 (with Peter Singer's response on pages 185-94).
• "Faith, reason, and alternatives to Genesis 1:1," Proceedings of the Jesuit Philosophical Association (2011): 29-47. For my related Windows game to illustrate the fine-tuning argument for the existence of God, click here: Genesis.
• "Reflections on the golden rule" (presidential address), Proceedings of the Jesuit Philosophical Association (2013): 11-23.
• "Persia and the golden rule," Religious Inquiries (Teheran, Iran) 2 (2013): 29-46. [On the golden rule in Persia and in Islam.]

And some of my book reviews are available online:

• Review of Morality and Universality, edited by Nelson T. Potter and Mark Timmons, Noûs 23 (1989): 555-57.
• "So why do anything?" (Review of Understanding Human Goods: A Theory of Ethics, by T.D.J. Chappell), London Times Higher Education Supplement (January 22, 1999): 35.
• "Peter Singer - Moral Hero or Nazi?" (Review of Singer and His Critics, edited by Dale Jamieson, and Ethics into Action: Henry Spira and the Animal Rights Movement, by Peter Singer), London Times Higher Education Supplement (October 8, 1999): 26.
• "Logic and superman" (Review of Logical Properties: Identity, Existence, Predication, Necessity, Truth, by Colin McGinn), London Times Higher Education Supplement (October 26, 2001): 28.
• "Big questions for party-goer" (Review of Kant: A Biography, by Manfred Kuehn), London Times Higher Education Supplement (April 12, 2002): 28-29.
• "Taxing question of the blue (or green) sideswiper" (Review of An Introduction to Probability and Inductive Logic, by Ian Hacking), London Times Higher Education Supplement Textbook Guide (May 31, 2002): 31.
• "Detached analysis, engaged nihilism" (Review of New British Philosophy: The Interviews, edited by Julian Baggini and Jeremy Stangroom), London Times Higher Education Supplement (October 25, 2002).
• Review of The Oxford Handbook of Philosophical Theology, edited by Thomas P. Flint and Michael C. Rea, Notre Dame Philosophical Reviews (September 20, 2009), 4 pages long.
• Review of Ethics and Experience: Life Beyond Moral Theory, by Timothy Chappell, The Philosophical Quarterly 61 (October 2011): 878-80.
• Amazon Review of James Murphy's War's Ends (April 7, 2015)
• Amazon Review of Mike Bushman's Doing Unto Others (April 18, 2015).
• Amazon review of Thomas Carson's Lincoln's Ethics (July 1, 2015).
• Amazon Review of Rami Shapiro's The Golden Rule and the Games People Play: The Ultimate Strategy for a Meaning-Filled Life (October 25, 2015).