Thomas Aquinas: An Evangelical Appraisal

At 800 years old, should old Aquinas be forgot and never brought to mind? 

Norman Geisler, a Thomistic philosopher (Ph.D., Loyola University), answers with an emphatic No! He argues that Protestant critics of Aquinas have misunderstood him. This introduction to the life and thought of Thomas Aquinas offers valuable insights in areas like faith and reason, epistemology, metaphysics, God’s nature, creation, human nature, government, ethics, and more. 

Originally published in 1991 (Baker Books) and republished in 2003 (Wipf&Stock), this second edition was revised and expanded by Dr. Geisler in 2013. He added a totally new chapter on human evil, rewrote most of the chapter on evil, and made other minor revisions and expansions in most of the other chapters. In 2025, four new appendices of content written by Dr. Geisler in 1998, 2002, 2014, and 2018 were added to the book. 

The book is available for sale only on Amazon.com. 

Paperback | Hardcover | e-Book | Audio Book

 

If you’d like to buy this book in bulk at a discount, feel free to contact us. 

 

If you want to report any typos, please feel free to contact us. 

 

If this book has been a blessing to you, please feel free let us know! (contact us)

 

 

NEWS

A translation into French by a Thomist and linguist who lives in Paris, France, may begin soon!

Bastion Books is also looking for a qualified translator to translate this book into the Spanish language.  If you know someone who is conversant with Thomism, proven in academic Spanish, has done some professional translation, and who might be interested in translating this book, please contact us.

1) The Contemporary Relevance of Aquinas        1

2) The Life of Aquinas                                             21

3) An Overview of the Thought of Aquinas        39

• Revelation               
• Faith and Reason
• Knowledge    
• Reality   
• God 
• Analogy       
• Creation  
• Human Beings 
• Ethics 
• Works on Aquinas 

4) The Bible                                                           49

• The Divine Authority of Scripture      
• God as the Author of Scripture           
• The Relation of the Divine and Human in Scripture 
• The Use of Human Literary Forms      
• The Inerrancy of Scripture                    
• The Superiority of the Bible                  
• The Role of Christian Teachers            
• The Place of Creeds                                
• The Interpretation of Scripture           
• The Literal Sense of Scripture             
• Sensus Unum or Sensus Plenus? 
• A Literal Understanding of Messianic Prophecy 
• The Influence of Aristotle 
• The Author’s Meaning 
• A Text in Context 
• The Use of Scripture in the Summa theologiae 
• Conclusion 

5) Faith and Reason                                          71

• The Relation Between Faith and Reason
• Reason Cannot Produce Faith 
• The Uses of Reason in Christian Faith 
• Divine Authority as the Basis of Faith 
• Human Reason Used to Support Faith 
• The Distinction Between Faith and Reason 
• Faith Described in Relation to Reason 
• The Meritorious Nature of Faith 
• The Formal Distinction between Faith and Reason 
• The Limitations of Reason 
• Reasons for Revelation 
• The Effect of Sin on the Mind
• Things above Reason 
• Faith, Reason, and Certitude

6) The First Principles of Knowledge

• The Importance of the First Principles
• The Meaning of the First Principles 
• The Definition of a Principle 
• The Definition of a First Principle
• Kinds of First Principles 
• Priority among First Principles 
• The Necessity of First Principles: Certainty and Certitude 
• Objective Certainty 
• Subjective Certitude 
• The Ontological Basis of First Principles 
• The Epistemological Origin of First Principles 
• All Knowledge Begins in Sensation 
• The Need for the Agent Intellect 
• First Principles Arise from Judgments, Not Apprehensions 
• An Epistemological Problem 
• How Can First Principles Be Known from Sensation?
• In What Sense are First Principles “Natural” Knowledge? 
• What Is the Precondition for Knowing First Principles?

7) Reality                                                               123

• The Challenge of Monism 
• The Historical Context 
• The Philosophical Argument 
• The Pluralistic Alternatives to Monism 
• Atomism: Things Differ by Absolute Nonbeing 
• Platonism: Things Differ by Relative Nonbeing 
• Aristotelianism: Things Differ as Simple Beings
• Thomism: Things Differ as Complex Being
• The Superiority of Aquinas’s Position 

8) God’s Nature                                                 139

• The Nature of God 
• Pure Actuality 
• Simplicity 
• God’s Immutability 
• God’s Eternality 
• God’s Unity 
• God’s Relatability 
• God’s Knowledge 
• God’s Will 
• The Nature of God Defended
• The Antinomy of Creation
• The Antinomy of Service
• The Antinomy of Relationship
• The Antinomy of Supreme Reality
• The Antinomy of Contingent Truth

9) God’s Existence                                            165

• The Arguments for God’s Existence 
• The Argument from Motion
• The Argument from Efficient Causality
• The Argument from Contingent Beings
• The Argument from Gradation of Perfection
• The Argument from Design 
• The Basic Metaphysical Proof for God 
• The Statement of the Metaphysical Argument
• A Restatement of the Metaphysical Argument
• Objections to Aquinas’s Arguments for God 
• Finite Beings Need Only Finite Causes 
• The Concept of a Necessary Being Has No Meaning 
• There Is No Way to Prove the Principle of Causality 
• Theistic Arguments Are Not Persuasive 
• An Infinite Series of Causes Is Possible 
• The Cosmological Argument Depends on the Invalid Ontological Argument 
• Necessity Does Not Apply to Existence, But Only to Concepts
• The Conclusion Does Not Prove a Theistic God 
• There Is No Need for a Here-and-Now Cause of Existence
• The Act-Potency or Contingent-Necessity Models Are Arbitrarily Imposed on Experience 
• The Cosmological Argument Commits Modal Fallacies

10) Human Nature                                           191

• The Origin of Human Beings 
• The Nature of Human Beings 
• Human Beings are Created 
• Human Beings are Contingent 
• Human Beings are Composed of Act and Potency
• Human Beings are Composed of Substance and Accidents
• Humans are Corporeal (Bodily) 
• Humans Have a Soul 
• The Special Powers of a Human Being 
• The Destiny of Human Beings 
• Resurrection 
• The Final Destiny of the Lost (Hell)
• The Beatific Vision for the Saved

11) Religious Language                                      217

• The Alternatives 
• Univocal Predication of God Is Impossible
• Equivocal Predication Leads to Skepticism
• Analogy Is the Only Adequate Answer 
• The Basis of Analogy in Religious Language
• Analogy Is Based in Causality
• The Use of Analogy 
• Kinds of Analogy – Extrinsic and Intrinsic
• The Analogy between God and Creatures 
• It Is a Causal Relationship 
• The Relation Is Intrinsic, Not Extrinsic
• The Relation Is Essential, Not Accidental
• The Cause Is an Efficient, Not an Instrumental One
• The Cause Is the Efficient, Not the Material Cause 
• Objections to Analogy Considered 
• Why select only some qualities from the world to apply to God? 
• Words divorced from their finite condition are devoid of meaning 
• Analogy rests on the questionable premise of causality as its basis 
• An analogous predication of God fails to identify the univocal element 
• The real relationship between Creator and creatures is not univocally expressible
• According to Wittgenstein, the distinctions among univocal, equivocal, and analogical expressions are obsolete 
• A general theory of analogy does not work

12) Evil                                                                      237

• The Reality of Evil 
• The Nature of Evil 
• The Dilemma of Theism about the Nature of Evil 
• A Response to the Dilemma: Evil is a Privation in a Good Thing 
• The Origin of Evil 
• The Nature of Free Will 
• Free choice is voluntary 
• Human Free will has the power of alternate choice
• A free choice is a self-caused action 
• Free choice is not of necessity 
• Free choice cannot be coerced
• Free choice is not destroyed by sin 
• The Purpose of Evil
• God has a Good Purpose for Permitting Evil
• God Will Bring Good Out of Evil 
• Permitting Evil is a Precondition for Achieving Higher Goods 
• God’s Providence and the Persistence of Evil 
• Physical Evil is not the Result of an Imperfect Cause
• Physical Evils Due to the Nature of the Physical World 
• God Causes Physical Evil Only Incidentally, not Directly 
• God and Gratuitous Evil 
• The Relation of God Providence to Fortune and Chance
• The Relation of God’s Providence to Fate 
• The Ultimate Victory of Good over Evil
• The Destructive Effects of Evil are not Total or Permanent
• The Eternal Blessedness of Saints in Heaven
• The Eternal Punishment of Sinners in Hell 

13) Law and Morality                                           265

• The Nature of Law 
• The Definition of Law 
• Law as a First Principle
• The Promulgation of Law 
• Kinds of Law 
• Eternal Law 
• Natural Law
• Human Law
• Divine Law 
• The Purpose of Law 
• Conflicting Situations 
• The Priority of Natural Law over Human Law 
• Laws Based on God’s Nature over His Will 
• The Letter versus the Spirit of the Law 
• Morality 
• The Cardinal Virtues
• The Divine Virtues

Epilogue                                                                 285

Select Bibliography                                             287

Appendices: 

1. The Major Writings of Aquinas              289
2. A Chronology of Aquinas’s Life              291
3. God, Angels, and Humans                      292
4. Thomism and Neo-Thomism (1988)    293
5. He’s Our Man: Christian History Interview (2002) 301
6. Does Thomism Lead to Roman Catholicism? (2014) 307
7. Who Was Thomas Aquinas? (2018)     319
8. About Norman Leo Geisler                     331

Endorsements for this Book

“This is ‘must reading’ for every thinking Christian. I am thrilled by this careful analysis of St. Thomas.” – R.C. Sproul, Emeritus Professor of Theology, Reformed Theological Seminary

“The book gives an understandable presentation of many of Aquinas’s major contributions and shows how they are relevant, at times even crucial to contemporary discussion. In the process Geisler strikes a credible blow against the current unfounded prejudice towards S. Thomas in evangelical thought.” – Winfried Corduan, Professor Emeritus of Philosophy and Religion, Taylor University

“Dr. Geisler is a man I have known and admired for many years. It is indeed the rare man who can find in an apparent enemy an ally. But Geisler’s study of Thomas Aquinas is far more than an instance of the old adage fas est et ab hoste doceri (it is right to learn even from the foe). He enables evangelicals and Catholics to see the immense range of truths that unite us, not as some least common denominator, but truths that are at the heart of our Christian faith.” – Ralph McInerny, Professor of Philosophy, University of Notre Dame, Director of the Jacques Maritain Center

“Paul tells us in Romans 1:20 that the invisible attributes of God ‘are clearly seen through the things that are made.’ He echoes the Psalmist who tells us that ‘the heavens declare the glory of God’ (Psalm 19:1). No philosopher in history has done a better job of unpacking the philosophical richness of Paul’s and the Psalmist’s proclamations than Thomas Aquinas. Evangelicals who ignore Aquinas’s thinking here and in other areas are doing themselves a great disservice. There is no better place to begin appreciating his philosophy than Dr. Norman Geisler’s excellent book. It should be in the library of every thoughtful Christian.” – Richard G. Howe, Provost, Norman Geisler Chair of Christian Apologetics, Southern Evangelical Seminary

“This book is an astute introduction to the philosophical thought of Aquinas for evangelical thinkers. The list of topics [is] extensive: faith and reason, religious language, Aquinas on the Bible, reasoning for God’s existence and nature, natural law, the human person. Its abundant citations acquaint the reader with Aquinas himself and open the door to deeper dimensions of his metaphysical thought.” –  John F. X. Knasas, Emeritus Professor of Philosophy, Center for Thomistic Studies, University of St. Thomas, Houston

“Dr. Geisler has hit a grand slam with Thomas Aquinas. This volume makes accessible the many Thomistic nuggets to the evangelical world. Whether you’re a theologian or lay person, this clear and understandable work offers crucial ideas for understanding the Bible, God, creation, reality, the relationship between faith and reason, and much more. This must-read book is an indispensable resource for any thinking Christian’s toolkit. Take and read!” – Joseph M. Holden, President, Veritas International University

“Thomas Aquinas is arguably the greatest mind Christendom has ever produced. Yet many Christians are unfamiliar with his life and extraordinary accomplishments. Norman Geisler has done a great service for evangelical Protestants by providing them with a general introduction to St. Thomas’s life and system of thought. Old Aquinas has indeed much wisdom to teach all branches of Christendom.” – Kenneth Samples, Senior Research Scholar, Reasons to Believe

“Some may be surprised that a well-known Christian leader, such as Norman Geisler, would propose greater evangelical appreciation of Thomas Aquinas. But, in fact, reading Aquinas will enrich the evangelical Christian’s theology, philosophy, and apologetics. In this book, Geisler seeks to give a basic explanation of the untapped riches of Thomistic theology and philosophy to the evangelical and to whoever is open to learning it. For this reason, I recommend this book as a beginner’s guide to those who are interested in learning from Aquinas but whose hearts falter at the prospect of having to learn the medieval scholastic literary method.” – Miguel Angel Endara, Professor of Philosophy and Apologetics, Veritas International University 

“Dr. Geisler’s appraisal of Aquinas is an absolutely essential read at a time in history when Aquinas’s works have been largely either forgotten, rejected, or misrepresented. Many of the modern and contemporary problems in philosophy and theology stem from a failure to read, understand, and apply a consistent Thomistic philosophical framework, which when done properly unveils the reality that most of these problems end up being but pseudo-problems. Dr. Geisler stands as a monumental figure in contemporary thought in the defense of orthodoxy, and toward the continued propagation of Aquinas’s necessary ‘bellowing resounding throughout the world’.” – Matthew J. Coté, Professor of Philosophy & Apologetics, Alaska Bible College

“Evangelicals must stop thinking of the medieval period as the long dark time between Augustine and Luther. Geisler’s critical but charitable engagement with Aquinas’s writings provides a helpful introduction to overturning some common misunderstandings about Thomas’ philosophy and offers an invitation to further study in the period.” – John R. Gilhooly, Professor of Philosophy and Theology and Director of the Honors Program, Cedarville University

“It is with great enthusiasm that I commend Dr. Norm Geisler’s evangelical compendium on the theological genius of Saint Thomas Aquinas. In this book, Dr. Geisler is both conductor and instrumentalist as he directs the concerto on the veritas Dei composed by the humble Dominican Friar. To all who have undergone their own intellectual born-again experience and to all who have yet to discover God’s philosophy: Tolle Lege! (“Take up and read!”) Then you will discover why it is the highest compliment to be called a Thomist.” – Kenny Rhodes, Visiting Scholar, Reasons to Believe