Come, Let Us Reason: An Introduction to Logical Thinking

by Norman L. Geisler, Ronald M. Brooks (Contributor)

The perfect introductory textbook, this simplified study of logic prepares readers to reason thoughtfully and to spot illogic in an argument.

Genres: Philosophy, Logic, Christian, Nonfiction, Theology, Reference

232 pages, Paperback

First published August 1, 1990

About the author

Norman L. Geisler (PhD, Loyola University of Chicago) taught at top evangelical colleges and seminaries for over fifty years and was a distinguished professor of apologetics and theology at Veritas Evangelical Seminary in Murrieta, California. He was the author of nearly eighty books, including the Baker Encyclopedia of Christian Apologetics and Christian Ethics. He and his wife lived in Charlotte, North Carolina.

Reviews

[John Martindale · Rating 1 out of 5]

In the beginning section covering Aristotelian logic, Geisler tried to hastily cover in about 40 pages what other textbooks took over 100 pages to explain. Geisler just dumped out multitudes of terms and concepts that left me frustratingly confused. I had to turn elsewhere to actually learn it all. Even after getting a grasp of deduction from other introductory texts, I still found, in returning to Geisler, his writing to be convoluted. Over all this is a simply terrible introduction to logic.
But my word, the worst thing about the book is that Geisler used it as a platform for his pet evangelical dogmas to frolic about. Ironically (considering the topic of the book), he often, quite embarrassingly so, engaged in fallacious reasoning in so doing. I'll mention a few examples I read that got me furiously scribbling in the margins of the book.

THE SLIPPERY SLOP FALLACY
After sharing about this fallacy, Geisler mentions “one notable argument that avoids this fallacy is “if you can't trust someone (or some book) that claims to be infallible in everything it says, then you can't trust it in anything. '”
Geisler continues to assert that since the bible claims to be inerrant and infallible, if it is mistaken in a single historical or scientific fact, we can't trust any of it and might as well toss the whole thing in the trash.
First of all, there is just so much wrong with his confident assertion that the bible claims itself completely inerrant and infallible. The verses he listed explicitly say no such thing and are themselves subject to different interpretations. Moreover, the original authors can't be said to even be referring to the whole "New Testament" for parts didn't even exist yet. And finally, the bible contains many independent books; even if one book claimed inerrancy, the claim doesn't hold true for the other books within the canon, which made no such claim. But yeah, even if it were the case that every book of the bible did claim inerrancy, Geisler's point that none of it could be trusted if it contained a single error, doesn't follow! The only thing that would be falsified is the claim of infallibility and inerrancy; everything else would either stand or fall based upon the evidence.
Suppose there is some factual error in the Old Testament, does that mean the bible cannot serve as one of our sources concerning ancient Israel? Can we not trust that Israel was conquered by the Babylonians? Must we conclude that Jesus didn't exist and wasn't crucified? Must we disregard the gospels as a source concerning the life and sayings of Jesus? Must we conclude that some of the moral concepts and truths within its pages must be discounted even when they ring true and are congruent with reality?
This all-or-nothing thinking--that either the bible is completely True or it is completely False-- creates a dangerous bubble. Geisler's bubble is made of steel; no amount of evidence could penetrate and convince him otherwise. But other evangelicals influenced by Geisler's bad reasoning may eventually find an error in the bible (they are not too hard to find), and it will unnecessarily be the utter ruin of their faith. Geisler offers a bad hypothesis, one that completely contradicts reality, and then sets up a false dilemma that sets people up for a fall.

THE FALLACY OF CONFUSING VARIOUS KINDS OF CAUSES
After writing about the different kinds of causes (Effectual, Final, Formal, Material, Exemplar and instrumental), he gave an example of where someone commits the fallacy confusing causes, when they say "If God determined all events, he must be responsible for all of the evil in the world" Geisler claims that thinking God is responsible for the evil he determined, is the result of confusing primary and secondary causes.

Geisler insisted early in the book that “We still experience our choices as free even though God both knew what we would decide and chose that we would decide it long before we did.” and later that “God is the primary cause of all things, and, as sovereign, he is the primary cause of all events by knowing them and willing that they be so” And finally, he states "Being in control, he knows all that will happen and gives his consent to them, but the direct and immediate causes of them are the secondary causes that are employed."
So Geisler has thrown in here a number of categorical universal statements that state ALL THINGS, and evil is among these things. Therefore, according to Geisler, God first chooses the evil that we must "freely" decide to do ourselves. God wills all evil, and God gives his full consent to all the evil that happens in the world, and finally, God is truly the primary cause of all evil. Every rape, every child molestation, and every murder was first determined, chosen, and willed by God. Genocide, ethnic cleansing, and all sadistic brutality are part of God's will that cannot be thwarted.
And yet, from some tortured illogical twist of insanity, Geisler thinks that if God accomplishes all his evil plans (which I am sure he'd say are for some higher good) through secondary means that He isn't responsible for evil!!!
So now, let's say I had a daughter who is an evil little brat, and for the good of humanity, I know she needs to die. But I know if I kill her with my own hands, I'd be responsible for murder (even though I was doing it for the higher good), and I can't have that! What might I do? Well, no worries, for I read Norman Geisler and know that if I have her murdered through secondary means, I will be completely innocent of her death. Of course, the killer has to freely choose to murder my daughter of his own free will. So, I'll just condition my son so that he hates her and, from his own heart, freely wants to murder his sister. I will also fully consent and allow him to stab her to death, though I could have easily prevented it. My son will think he is freely choosing to murder his sister, but really, he is only doing what I already chose for him. So now, only my son who actually shed the innocent blood is guilty, and I am not responsible for any wrong, Right? wrong!

After saying God willed, determined, consented, and chose all things (including all evil) and how God is the primary cause of all evil but not responsible because he does it through secondary means. Giesler then muddies the water by using terms that completely contradict everything he had been saying. He wrote, “When God created beings with free will, he knew that there was a possibility for evil, but it was necessary to allow that in order to have creatures that were truly free. Even when God allows someone to do evil, she is still morally responsible for the evil that she does. A secondary cause acts on its own, not simply as a mechanism of the primary cause. Responsibility for evil must be given to the secondary cause that chooses to act in an evil way, not the primary cause that allows the freedom of creation.” Possibility? Truly free? Acts on its own? Not simply a mechanism of the primary cause? Geisler, you wrote earlier “God both knew what we would decide and chose that we would decide it long before we did.” Trying to slip these terms in, in order to try to get the Primary cause off the hook for causing all evil through secondary means, doesn't get you off the hook! You mentioned early in the book that free will is only a feeling, this sense we are making our own decisions when in reality we are only doing what God pre-determined we would do! Speaking of which...

THE FAULTY DILEMMAS FALLACY
One example he gave of a faulty dilemma is that everything happens either by free will or by divine determinism. His solution is to offer a 3rd path that he confidently thinks avoids the dilemma by stating both are true and compatible. He thinks God pre-determining everything (meaning it could only happen one way) is compatible with “free will”. But he only pulls this off by committing the equivocation fallacy. For all who present the dilemma, who actually believe in freewill, understanding free-will to mean that in certain cases, when one did Y, one could have truly done X instead. If we could rewind and do things over, we could and might choose X instead of Y.
To solve the so called false dilemma, Geiser wrote “freedom isn't hindered by determinism, because the person doesn't know his choices is determined and feels that the choice is his” So we are all marionettes controlled by the divine Puppet master, but because God placed us under the illusion that we are free and deluded us with a feeling of freedom, we are somehow responsible for the evil God made us do?! Common Geisler! You totally redefine “free will” to mean nothing but a delusion and a feeling, and cannot see that you have therefore totally selected determinism!
The true dilemma is between determinism and indeterminism. If determinism, then man is not responsible for his actions, even if he is deluded into thinking he had a choice; this wasn't the case, he couldn't have done otherwise. To use an extreme example, consider the choices Hitler made. Geisler is confident that God, before the foundation of the world, predetermined everything Hitler did; he couldn't have done otherwise. God is in absolute control. But Geisler thinks that since God also determined Hitler to be under the illusion that he freely chose wickedly, Hitler is therefore responsible, though God made him do it. Common Geisler, can you not see how absolutely convoluted this is?
Indeterminism means that, if we could go back in time, re-roll the dice, so to speak, Hitler might have made different choices, and things might play out differently. Geisler would reject this and say that if we rewound, and history replayed a million times, it would always play out the same way according to God's pre-written script. If man couldn't have done otherwise, if the rapist had to rape the woman, because God determined him to do so, it is simply disgusting to think that man is responsible and God is off the hook because that man was under the illusion that he had a choice!

THE FAULTY ANALOGY FALLACY
One example Geisler gave is “If man changes, when he changes his mind, then God changes when God changes his mind.” But embraces the Greek philosophical understanding of God and thus cannot believe God ever changes, so for him this has to be a faulty analogy.
But now, in order to convince us that the statement about God changing his mind implying change in the Godhead is a faulty analogy, Geisler wrote how God changing his mind is merely a metaphor, like when the bible says God has hands or wings. This is a category mistake, though. Consider when the bible says God has wings, it is a metaphor and thus actually represents something. When we say “He covers us with the shadow of his wings,” we are referring to actual protection in a poetic way. But God changing his mind is a totally different category. ” Geisler trying to turn this statement, 'God changes his mind,' into a metaphor doesn't work. For if God cannot change, what does it mean when the bible says God changes? What do these supposedly metaphorical statements actually represent? Geisler wouldn't have an answer; he pretty much is just saying these are meaningless statements or that they mean the opposite of what they state. When the bible says God changes, it really means He doesn't change. When the bible claims there is a before for God, it really means there is no before for God. Welcome to the logical world of Geisler! I'd suspect that there is NO way that even the ALL-powerful God to convince Geisler otherwise. Heck, God tried, he stated it again and again how he changed his mind, he even pointed to how it was one of His praiseworthy attributes, but God is merely wasting his breath, for Geisler in this regard is immutable

[Jacob Aitken · Rating 5 out of 5]

For a person who has grown up in the television age and not used to rational thinking (90% of America), this book is pivotal for an understanding of logic. Upon first glance this book is hard to read because we are not used to thinking in terms of complex propositions. And, like any textbook, the more that you put into it, the more you will get out. An understanding of loigc is necessary for even a superficial reading of the Bible. St. Paul in every sentence is using logic to its deadly effect. To read Romans and Galatians without reasoning properly is...

The bright moments of this book is that the employment of logic opened up a new world for me. I fault Geisler with certain examples he used. Sometimes he did not go far enough. That aside, tis should give the student an understanding of the basic content and how to use it. After mastering this book I would recommend moving on to *Introduction to Logic" 11 ed. by Copi and Cohen. For a quick refreshment of logic see chapter two of *Philosophical Foundations for a Christian Worldview* by Moreland and Craig (I do not entirely endorse other parts of that book, but chapter two is pivotal).

Another limitation to the book is that most logical discourse today is done in the field of analytic logic, which Geisler usually avoids.

[David Haines · Rating 4 out of 5]

I honestly did not know what to expect when I opened this book. It claims to be a christian book that could be used in a course on Introduction to Logic - that is, a christian logic textbook. It is just that. No book is perfect, and this one has its share of failures. However, It covers most of the important aspects that would be needed in an introduction to logic, and then some. Many of the examples come from the Bible, or theological debate. Each chapter is followed by a number of exercises that reinforce what was learned in the chapter. An appendix gives a rudimentary explanation of truth tables, and there are a glossary and an index at the end which are quite useful. All in all it is an interesting book, and worth reading at least once in one's life.

[Taylor Simpson · Rating 4 out of 5]

...you can't avoid studying logic, so you might as well know what you're doing.

Norm Geisler's and Ronald Brooks' introduction to logic, Come Let Us Reason (CLUR), is a solid...well, introduction to logic. What else is there to say?

I had specific information I was looking for coming into this book, and literally all of that information was presented in the first chapter. However, I stuck around to the end and was not disappointed with the rest of the material.

CLUR is an excellent mini-textbook to get someone's feet wet in logic. Having only taken one introductory logic course in college almost a decade ago, I can't sit here and tell you I was already an expert in everything this book contains. Through my years of lay-level (and sometimes intermediate-level) studying of theology and philosophy, I've gotten acquainted with logic and its corollaries by necessity, but I've actually never formally read any kind of basic logic material before CLUR. Sections and chapters of many different books are devoted to logic in varying degrees, but this is my first encounter with an all-logic book.

The introduction of CLUR is excellent in laying out the relevant background for what exactly logic is and its importance in the life of a Christian. And, really, that's the most interesting aspect of CLUR: it's basically an introduction to logic with a theistic lens applied. That's not necessarily good or bad, but that's what you get here. I could see non-Christians being turned off by that, but, then again, most of them would probably be trying to learn about logic from any number of secular logic books. That's kind of the whole point of CLUR, according to the authors: to give Christians specifically a leg up in logical thinking. There are all kinds of examples and scenarios presented through the book to illustrate different kinds of syllogism and fallacies and other things that are directly relevant to the Christian in need of encouragement with their critical faculties.

I will say, though, that after a solid introductory chapter that is very accessible even to those not yet acquainted with logic, the next two chapters get pretty deep pretty quickly. In discussing the categorical syllogisms, the technical terms and symbols pile up rapidly and, even though I'm fairly comfortable with the rest of the content of the book, I almost stopped reading in the third chapter. I just felt like the explanations moved really quickly and there were important pieces I was missing, even when I went back repeatedly to re-read. I don't necessarily think this is the fault of the authors--logic is just very involved sometimes; you really need someone like a teacher in front of you answering your questions--but this was a big sticking point for me. I decided to keep going and push through to the next chapter and I'm glad I did. The remainder of the book deals with material that was much more accessible, and was in large part a helpful review for someone like me who is relatively familiar with the other types of syllogisms.

I think CLUR is a very good resource for almost anyone. It will be a handy reference in the future for me when I need to review a few fallacies or when I'm in the mood to finally tackle categorical syllogisms once and for all. But I'm also convinced that even those who know very little about logic in a formal sense can benefit greatly from the clear teaching of Geisler and Brooks. Logic is an incredibly important area of knowledge to master--in fact, as the pull-quote above suggests, it's THE subject we need to maser--and CLUR is a great place to start for those interested in taking a shot at it.

[Christopher Riley · Rating 5 out of 5]

Great book to begin to study logic. But anyone and everyone can read this. Some ideas may take some time to really soak in; but a re-reading of the paragraphs or chapters is really worth it. After all, Christians use logic, need to be logical, and should be so in talking about their beliefs as well as in conversation on any topic. This book really brings it home in helping us to understand why we believe the things we say we do and better helps us to share with others logically what views that are most dear to us. I am sure the non-Christian will have equal value from reading this readable presentation.

[Joy E. Rancatore · Rating 4 out of 5]

Come, Let Us Reason presents an introduction to logic from a Christian worldview. The book includes ten chapters full of analogies and examples to aid in learning. In addition, the chapters have accompanying exercises that enable students to put into practice what they've learned through reading. I recommend this to anyone who wants to learn how to think and read and discuss logically. I also recommend it to homeschoolers or other teachers looking for a book to use as a base for high school logic.

[Luke Nix · Rating 5 out of 5]

Great book for any Christian who wants to learn to think more clearly. Check out my chapter-by-chapter review here: http://lukenixblog.blogspot.com/2017/...

[Sean McGowan · Rating 4 out of 5]

Very good.

[Rodeweeks · Rating 1 out of 5]

Extremely difficult to understand, but at the same time I get the feeling that the authors are trying too hard to make their own beliefs seem logical

[Brandon · Rating 5 out of 5]

This is a great book, but not for casual reading. When you are ready to learn to think clearly and apply logic, this is your book. However, I would not recommend it for your first foray into the idea of logic. This is more of a textbook with exercises at the end of each chapter.

Plan to take the long journey with this book. It will be worth it.

[Oshea · Rating 5 out of 5]

I really enjoyed this book. It was hard work sometimes going over some of the homework parts of the book; however, it did add to understanding the subject better. I have read most of Gordon Clark's book on Logic and part of Kreeft's book on Socratic Logic and I found Geisler to be my favorite. Geisler throws one straight into syllogisms, which I liked--although for someone who never gave logic a thought might find this a little difficult. At any rate, I like how Geisler used Scripture throughout the book; however, he also has great non-Christian examples. He even has a chapter on logic in literature, which is fantastic. His chapter on non-formal logic is to-the-point and well written with good examples.
Overall I grew in my understanding of not just logic, but Scripture and Logic. Jesus is called the logos for reason: no pun intended. That is, in a nut-shell: Logic is the Structure for the Christian thinking, and the Scripture is the content for Christian thinking. This simply means I know the Bible better and I am able to discern when anti-Christian thoughts make fallacious statements.
After my study of logic, I would make it a required course for all children along side math and grammar. Moreover, I would make it a first primer for biblical hermeneutics. Wait, back in the day before the Puritans and Christians were kicked out from control of school this was a requirement.

The two cons of the book is how fast Geisler dives into the subject--this is subjective because I like that, however, for some this would be a negative. The other is Geisler's non-Scriptural understanding of human free-will, which in at least two places, makes him commit a fallacy about his deference of it. It would be better if he would stick to the logic and scripture, which teaches if God is sovereign over your mind, then "relative" to God you are not free. That is, if the question is "relative" to my own experience then I experience freedom. But if the question is "relative" to God's own sovereign action over my soul, then no, I do not have freedom: this is how I would suspect most to mean by asking about free-will in context of the Christian God. Bondage of the Will by Martin Luther would be a better read on this subject.

[Glenn Crouch · Rating 4 out of 5]

For me, this was a good "refresher" course on Logic - and even better to get it in a Christian Apologetic framework.

There would be much benefit if more Christians were to come to understand the mechanics behind "reasoning", thus they would be able to put forward better arguments - I direct this at myself as well. Even though I have a Mathematical background, it is easy to get caught up in the emotional side of things and to make many of the "fallacies" explained in this book.

I think the Authors have done a good job and would recommend it - and will no doubt read it again in the future :)

[Philosonerd77 · Rating 4 out of 5]

Geisler does a great job at making logic a lot easier to understand. The examples are all from the bible,theology and apologetics because it was written with Christians in mind. This book only goes into the very basics of logic. If you came onto the book thinking that there was going to be modal logic,predicate logic or any other more advanced topics in logic then you will be very disappointed. This book is a starting point and from this book you can move up the ladder to other logic texts.

[Ryan Yoder · Rating 5 out of 5]

Having not studied formal logic before this book I was in over my head. Still, I advise one dive right it. It is clear enough if one takes the time to study the material and not merely read it.

It's a book to open the mind to the extensive possibilities of honorable debate. One, by Gods grace, will close the back cover determined to not only combats errant views but the errant arguments for his own views.

[Lance · Rating 3 out of 5]

A good introduction to semi-formal logic. Somewhat disconcerting in it's opening thesis which suggests a reading of John chapter one which reads, "In the beginning was the Logic." Nonetheless a good read for those wishing to encounter a Christian understanding of largely Platonic logic.

[Brit · Rating 5 out of 5]

As an introduction to logic, this is an excellent book. Reading each chapter carefully and doing the exercises after each chapter gave me a better understanding of logic, so I can tackle a more in depth material.

[Pondering Pastor · Rating 5 out of 5]

Good intro to Logic.

[Christian Proano · Rating 5 out of 5]

A must read twice and reviewing for refresh from time to time. This is an excellent book.