Why would someone smart enough to invent calculus believe in God? And what kind of God would they believe in? Gottfried Wilhelm Leibniz (1646-1716) wrote extensively to answer these questions. A brilliant German logician, mathematician, and father of differential and integral calculus (independently of his contemporary Sir Isaac Newton—who also believed in God), Leibniz let none of his beliefs about God go unscrutinized.
This series condenses the results of that scrutiny: four arguments toward the biblical God and their implications. We’ll walk through Leibniz’ arguments one at a time, first in syllogism, then in detail, then in simple English. Ready?
First, some terms:
- Contingent: Owing its existence to another thing. Contingent things “have nothing in them to render their existence necessary”.
- Necessary: Existing without dependence on anything, and therefore must Something “carrying the reason of its existence within itself,” and thus “the opposite of which would imply contradiction”.
- Sufficient reason: A “reason which has no need of another reason.” A self-sufficient reason.
- Principle of Sufficient Reason (PSR): “No fact can be real or existent, no statement true, unless there be a sufficient reason why it is so and not otherwise, although most often these reasons cannot be known to us.”
Argument 1: God Is
From The Principles of Nature and of Grace, The Monadology, and On the Ultimate Origin of Things.
“The first question which should rightly be asked would be, ‘Why is there something rather than nothing?’” That’s where Leibniz’ first argument begins:
- Nothing exists without sufficient reason (PSR)
- The universe exists
- Sufficient reason for the universe’s existence cannot be found in any series of contingent things
- Therefore, the universe must exist due to a necessary thing
- First, this is self-evident, and the foundation of science. Second, as the linchpin of rationality, the PSR must be preserved against instant arrival at our conclusion. Supposing some things exist without sufficient reason, one may suppose the desired thing does, lifting the burden of proof arbitrarily. Once the absoluteness of the PSR has been denied, there is no self-evident a priori principle by which to know when some things do and others do not require sufficient reason (and if we assume a priori that nothing requires sufficient reason, we may again arrive instantly at our conclusion, unstopped by contrary reason). From here, no reasonless entity or class of entities can be truly proven a posterori, since there is no way to prove which phenomena are actually reasonless and which are simply not yet understood, either by individual case or by appealing to a class (which needs prior establishment by individual cases). Thus, counters to the PSR cannot escape argument from ignorance and therefore perpetual vulnerability (and as history suggests, very great vulnerability) to future discoveries rendering them obsolete, so the PSR wins by the default of self-evidence. Finally, objections regarding impossibility of proving causation are irrelevant to the PSR, since causation is only unprovable insofar as it is indistinguishable from perfect correlation, but even perfect correlation would suffice to imply a sufficient reason from an existence.
- This is self-evident. Furthermore, since the universe is defined as a total existence (everything observed or assumed, or everything in space and time) by definition it both exists and is the largest thing in existence. Supposing all else is an illusion, there must still be a consciousness to be illuded (cogito, ergo sum ), and that consciousness would be the total existence and therefore the universe. Supposing a multiverse exists, the universe must still be equal or greater, being the total existence and any total quantity (“-verse”) being smaller when divided by several (“multi-”) than when divided by one (“uni-”). Thus, some “total” exists, and is the “universe” of this premise.
- By definition of contingent, necessary, and sufficient reason. In any series of reasons “however infinite it may be” that “only involves other contingents, anterior or more detailed, each one of which needs a like analysis for its explanation, we make no advance”. An infinite circle of contingencies also makes no advance since time must still be linear, and even if it were not, the entire package would still require sufficient reason. Therefore “the final reason of things must be found in a necessary substance”.
- “Therefore it must be that the sufficient reason which has no need of another reason be outside this series of contingent things and be found in a substance which is its cause, or which is a necessary being, carrying the reason of its existence within itself; otherwise we should still not have a sufficient reason in which we could rest. And this final reason of things is called God.” That is, the PSR requires a necessary thing, which we here name.
The Bottom Line:
Because all existing things must be justified, and contingent things cannot suffice, a necessary thing must exist, which Leibniz calls “God”.
So what? Right now, “God” is a meaningless label. What if the universe itself is this necessary thing? Leibniz has just begun—stay tuned for Part 2!
 Belaval, Yvon and Look, Brandon C. “Gottfried Wilhelm Leibniz.” Encyclopædia Britannica, www.britannica.com/biography/Gottfried-Wilhelm-Leibniz. 2019.
 Leibniz, Gottfried Wilhelm. Theodicy: Essays on the Goodness of God, the Freedom of Man and the Origin of Evil. Project Gutenberg, 2005.
 Leibniz, Gottfried Wilhelm. “The Principles of Nature and of Grace.” Discourse on Metaphysics, On the Ultimate Origin of Things and Other Principal Essays. Translated by George Martin Duncan, George R. Montgomery, and Robert Lattar, Ukemi Audiobooks, 2019.
 Leibniz, Gottfried Wilhelm. “On the Ultimate Origin of Things.” Discourse on Metaphysics, On the Ultimate Origin of Things and Other Principal Essays. Translated by George Martin Duncan, George R. Montgomery, and Robert Lattar, Ukemi Audiobooks, 2019.
 Leibniz, Gottfried Wilhelm. “The Monadology.” Discourse on Metaphysics, On the Ultimate Origin of Things and Other Principal Essays. Translated by George Martin Duncan, George R. Montgomery, and Robert Lattar, Ukemi Audiobooks, 2019.
 That is, “I think, therefore I am,” the famous a priori proof of, at a minimum, one’s own consciousness. Descartes, René. A Discourse on Method. Project Gutenberg, 2008.