The Logic in God
by Joshua Rasmussen
Logic is about rules of reason, such as the rule that nothing can be both true and false simultaneously. Why do such rules exist? And how do mere molecules and chemical reactions discover these rules?
I want to share with you some recent developments in my own thinking about the rules of reason. As a philosopher, reason has been one of my favorite lights. Yet I’ve only recently been shining reason upon itself. When I look back at my initial thoughts about logic, it is evident to me that I underestimated, undervalued, and underappreciated the reality of the things I see most clearly in my own mind.
In what follows, I will share why I now think the rules of reason are part of the foundation of existence. First, I will explain why I think the principles you see with your mind are not merely in your mind. Then I will motivate a hypothesis about how these principles fit inside a perfect mind.
Logic Is Not Merely in Your Head
To begin to think about logic, let us consider an example of a logical principle. Consider the law of identity:
(I) For any x, x is x.
This principle is manifestly true. Everything is itself. I am me. You are you. This computer is this computer. There are no counterexamples: nothing is not itself.
But what is this principle? What is its nature? I will show how (I) points to a logical landscape that exists out there—beyond your head. I will offer three independent considerations.
First, the truth of (I) doesn’t depend upon you. Before you were born, it was true that everything is what it is. Rocks were rocks. Blades of grass were blades of grass. Principle (I) describes reality whether or not you exist.
Imagine if that were not so. Suppose instead that before you were born, some rocks were not rocks. Some blades of grass were merely squirrels. Then you come along, and suddenly, everything begins to obey (I) for the first time. Rocks become rocks. Grass becomes grass. Surely, this scenario is absurd: the rules of logic don’t hold their breath for you.
In fact, one of the principles of logic (called K) is that the principles of logic are themselves necessary. They cannot not hold. Thus, (I) cannot not hold. In other words, (I) is true no matter what, even if you aren’t around.
As you may expect, there is some debate among philosophers about how to interpret the necessity of logic. Rather than enter the details of the debate here, I will refer to an article where I go into more detail: “From Necessary Truth to Necessary Existence.” The gist of the article is that logic cannot be necessarily true unless it is necessarily real—for nothing can be anything unless it is something.
My first reason, then, to think logic isn’t (merely) in your head is this:
1. Logic is necessary.
2. You are not.
3. Therefore, logic doesn’t depend upon you.
To be clear, when I say logic doesn’t depend upon you, I do not mean that your sight of logic doesn’t depend upon you. Your sight of logic does depend upon you. When you see beams of logic within your mind, your sight cannot exist without you. Yet, it would be a mistake to infer that what you see depends upon your sight. What you see is itself necessary (e.g., it is necessary that every x is x), whereas your sight is not.
Here is a second reason I’ve come to think logic transcends you (and me!). It’s about the nature of truth. I’ve become convinced that the best account of the nature of truth is in terms of correspondence with reality (see my volume Defending the Correspondence Theory of Truth). For example, <my cat is on the mat> is true if and only if there is a real cat on a real mat. Truth is about reality. If that is correct, then logical principles can only be true if they correspond with actual reality. Call the reality that logical truths correspond to ‘the logical landscape’.
What is the logical landscape?
Could the logical landscape just be your thoughts? I don’t think so. Your thoughts can be mistaken. Logical truths cannot be.
More fundamentally, your thoughts are the wrong category. Your thoughts are bearers of truth, not makers of truth. To illustrate what I mean, suppose you think some cat is on a mat, and suppose your thought is true. What makes it true? Not that very thought. Rather, what makes your thought true is the reality the thought is about—e.g., a cat, a mat, and their relationship. Similarly, what makes a thought about logic true is not that very thought. Rather, a logical thought is true by corresponding with a logical reality. So if your very first logical thought happens to be true, the reality that makes that thought true must be something other than your logical thought.
In general, nothing in you makes it true that rules of reason hold. Consider, for example, that it is true that if there were five unicorns, there would be more than four unicorns. No molecules in your head make that true. This principle is not about molecules. What makes it true, rather, is an abstract beam in an abstract, logical landscape.
Some people have suggested to me that logic is merely descriptive. But what does it mean to be descriptive? What does logic describe? If logic is descriptive, then logic describes something. That is my whole point: logic describes something (a logical landscape), which exists independently of our description of it.
Here is a third reason to think logic transcends you. This reason is based upon our ability to communicate with each other. You and I can communicate logical principles with each other. But how? Consider that you have your own private thoughts about (I), while I have my own private thoughts about (I). How do we ever find out that we are thinking about the same principle? If the logical principles you see hide exclusively inside your mind, how could you ever communicate to me what you see? How can you communicate the logical beams you see inside of you?
I have come to think that the best account of how we can communicate logical principles is in terms of a common logical reality. When you see the logical landscape, what you are seeing is not merely a painting inside your soul. Rather, you are looking through a window to see something that I can also see. The logical landscape is not wholly inside your head, my head, or Fred’s head. Rather, the logical landscape is something we can see in common. This common sight explains how we can talk about the same logical principles.
In summary, I offer three reasons to think logic isn’t merely in your head. First, logic is necessary, whereas your head is not. Second, logical principles are objectively true, yet nothing in your head could make these logical principles true. Third, our ability to talk about logical principles makes the most sense, it seems to me, if we are talking about something in common (not merely in someone’s head). By the light of these reasons, I infer that logic exists out there.
Logical Reality Is Part of Supreme Reality
I will close this article with a brief note about the relationship between logic and God. Rather than provide a deductive argument for the conclusion that logic can only exist if God exists, I will instead show why I think theism successfully predicts and explains the reality of logic.
The existence of logic is unsurprising if God exists. If God exists, a perfect mind exists. If a perfect mind exists, perfect thinking exists. All perfect thinking is logical. No perfect thinking is illogical. Therefore, logic is a framework for perfect thinking. So if perfect thinking exists, then logic exists.
Not only is the existence of logic unsurprising on theism, so is the nature of logic. As indicated above, logic has a necessary nature; the logical landscape cannot be created or destroyed. Theism predicts this very result. For if God exists, God’s perfect nature cannot be created or destroyed. God’s perfect nature includes the framework for perfect thinking, which is logic. Therefore, if God exists, then logic cannot be created or destroyed. This prediction matches reality.
We get a bonus result. Theism also provides resources to explain why any beings discover logic. Imagine, by contrast, that reality begins with a purely mindless foundation. In that case, it is puzzling how there could be any rules of reason out there. Moreover, there is then no reason within the fabric of reality for anything to become “aware” of logical principles. What explains that? Without God, the existence, nature, and discovery of logic are surprising (to say the least).
I have come to think, therefore, that theism provides a simple, non-arbitrary account of the existence and nature of logic. On theism, reality includes a supreme foundation. A supreme foundation would include a supreme nature, which itself includes a supreme framework for supreme thinking—i.e., logic. I have never seen anyone propose a candidate alternative hypothesis that is as simple and that predicts these same results.
We may summarize the results as follows:
1. Theism predicts that (i) rules of reason exist, (ii) continue to exist, (iii) aren’t merely in your head, and (iv) are discoverable by beings like you.
2. These predictions match reality.
3. No simpler hypothesis (that I have seen) makes those same predictions.
While there is certainly more to consider, these results are one reason to think that logic is rooted in God.[1]
Notes
[1] For more on the relationship between God and reason, see “Foundation of Reason” in my volume How Reason Can Lead to God (2019).
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Joshua Rasmussen, Ph.D., is a professor of philosophy at Azusa Pacific University. Rasmussen specializes in questions about existence and minds. He is the author of five books, including How Reason Can Lead to God (2019), The Bridge of Reason: 10 Steps to See God (2018), Is God the Best Explanation of Things: A Dialogue (2019, with Felipe Leon), Defending the Correspondence Theory of Truth (2014), and Necessary Existence (with Alexander Pruss; 2018). To get more resources on worldview development, visit his website joshualrasmussen.com or YouTube channel, Worldview Design.
Image by Şahin Sezer Dinçer from Pixabay
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