Cosmological
Kalam
(P1) Everything that begins to exist has a cause. Something cannot come into being from nothing.
(P2) The universe began to exist.
(C1) Therefore, the universe has a cause.
(P3) If the universe has a cause, then an uncaused, personal Creator of the universe exists who sans the universe is beginningless, changeless, immaterial, timeless, spaceless, and enormously powerful. Personal: The first state of the universe cannot have a scientific explanation, since there is nothing before it, and therefore, it cannot be accounted for in terms of laws operating on initial conditions. It can only be accounted for in terms of an unembodied mind and his free volitions, a personal explanation.
(P4) The universe has a cause.
(C2) Therefore, an uncaused, personal Creator of the universe exists who sans the universe is beginningless, changeless, immaterial, timeless, spaceless, and enormously powerful.
Contingency
(P1) Everything that exists has an explanation of its existence, either in the necessity of its own nature or in an external cause. (modest PSR) 17th century Leibniz original 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."
(P2) If the universe has an explanation of its existence, that explanation is grounded in a necessary being.
(P3) The universe exists.
(C1) Therefore, the universe has an explanation of its existence (from P1, P3).
(C2) Therefore, the explanation of the existence of the universe is grounded in a necessary being (from P2, C1).
(C3) Therefore, a necessary being exists (God).
Teleological
Cosmic Fine-Tuning
(P1) The fine-tuning of the universe is due to either physical necessity, chance, or design. By "fine-tuning" we mean that the fundamental constants and quantities of nature (e.g., the strength of gravity, the cosmological constant, the distribution of mass-energy in the early universe) fall within an extraordinarily narrow range that permits the existence of physical, interactive life. If these values were even slightly different, no life-permitting universe would exist.
(P2) It is not due to physical necessity or chance. Physical necessity would mean that the constants could not have been otherwise; chance would mean that they just happened to fall in the life-permitting range with no purpose or guiding intelligence. The probabilities involved, and the independence of the constants from the laws of nature themselves, strongly undermine both of these explanations.
(C1) Therefore, it is due to design.
Applicability of Mathematics
(P1) If God does not exist, the applicability of mathematics to the physical world is just a happy coincidence. On naturalism, mathematical entities (numbers, sets, functions, equations) are non-physical and causally inert. They cannot cause anything in the physical world. So if there is no divine mind ordering reality, the fact that the physical universe behaves in precise accordance with abstract mathematics is, at best, an unexplained coincidence.
(P2) The applicability of mathematics to the physical world is not just a happy coincidence. Mathematics does not merely organize data after the fact; it successfully predicts new phenomena (e.g., planets, radio waves, the Higgs boson) using highly abstract structures (imaginary numbers, higher-dimensional spaces, etc.). As Eugene Wigner put it, the “unreasonable effectiveness of mathematics” is so striking that he called it a “miracle which we neither understand nor deserve.”
(C1) Therefore, God exists.
Moral & Rational
Moral Argument
(P1) If God does not exist, objective moral values and duties do not exist. Without God, there is no objective reference point for right and wrong beyond individual or cultural opinion. On atheistic naturalism, humans are accidental products of blind processes; moral judgments then reduce to subjective preferences or social conventions, not binding truths that hold regardless of what anyone thinks.
(P2) Objective moral values and duties do exist. Our moral experience strongly testifies that some things are really good or evil, right or wrong (e.g., love vs. cruelty, justice vs. child abuse). As surely as we trust our sense experience of the physical world, we trust our moral experience that certain acts are objectively wrong for everyone, always, regardless of opinions or cultures.
(C1) Therefore, God exists.
Free-Thinking Argument
(P1) If robust naturalism is true, then God or things like God do not exist. Robust naturalism is the view that only physical things exist...no God, no immaterial souls, no abstract minds. Reality is exhausted by space-time, matter/energy, and the laws of nature.
(P2) If God or things like God do not exist, then humanity does not freely think in the libertarian sense. On a purely naturalistic picture, all human thoughts are the result of prior physical causes (e.g., brain chemistry, genetics, environment). This yields at best determinism (or indeterministic randomness), not genuine libertarian freedom to choose between alternatives in our thinking.
(P3) If humanity does not freely think in the libertarian sense, then humanity is never epistemically responsible. To be epistemically responsible...to be genuinely praiseworthy or blameworthy for what we believe...we must have some control over our thinking: we must be able to assess reasons, weigh evidence, and choose between competing beliefs. If our beliefs are entirely fixed by non-rational, prior physical causes, we are not truly responsible for holding them.
(P4) Humanity is occasionally epistemically responsible. In ordinary life we routinely treat people (including ourselves) as genuinely responsible for at least some of their beliefs...e.g., for ignoring evidence, being intellectually dishonest, or carefully weighing arguments. Our practices of rational praise and blame presuppose that people sometimes can freely choose how to respond to reasons.
(C1) Therefore, humanity freely thinks in the libertarian sense. (from P3 and P4, modus tollens)
(C2) Therefore, God or things like God exist. (from P1 and P2 and C1)
(C3) Therefore, robust naturalism is false. (from P1 and C2, modus tollens)
(P5) The biblical account of reality is one possible explanation for the existence of God, things like God, and the libertarian freedom of humanity.
(P6) If the biblical account provides a better explanation of these facts than alternative accounts, then it is reasonable to accept it as the best explanation.
(C4) Therefore, if the biblical account provides the best explanation, it is reasonable to accept it. (from P5 and P6, abduction to the best explanation)
Evolutionary Argument Against Naturalism (EAAN)
(P1) If naturalism and unguided evolution are both true, then the probability that our cognitive faculties are reliable is low or inscrutable. On naturalism, humans are the result of unguided evolutionary processes aimed at survival and reproduction, not at producing true beliefs as such. Evolution selects for behavior that enhances fitness, whether or not the underlying beliefs are true.
(P2) If the probability that our cognitive faculties are reliable is low or inscrutable, then we have a defeater for trusting the deliverances of those faculties. If you have good reason to doubt that your thinking is generally truth-tracking, then you also have good reason to doubt the beliefs produced by that thinking...including your belief in naturalism and evolution themselves.
(P3) If we have a defeater for trusting our cognitive faculties, then we have a defeater for any belief produced by those faculties, including belief in naturalism and unguided evolution. Belief in naturalism and in the truth of evolutionary theory is itself formed by our cognitive faculties. So if those faculties are undercut, these beliefs are undercut as well.
(P4) Therefore, if naturalism and unguided evolution are both true, we have a defeater for believing that naturalism and unguided evolution are true. (from P1–P3)
(C1) Therefore, naturalism is self-defeating and cannot be rationally affirmed together with unguided evolution.
(P5) Theism offers a better explanation of the reliability of our cognitive faculties than naturalism with unguided evolution. On theism, a rational God creates humans in His image with cognitive faculties designed for truth, not merely for survival. This gives us a positive reason to trust our minds as generally reliable.
(C2) Therefore, the reliability of our cognitive faculties provides evidence in favor of theism over naturalism.
Modal Ontological (Maximal Greatness)
(P1) It is possible that a maximally great being exists. A "maximally great being" is one that has maximal excellence (omnipotence, omniscience, moral perfection, etc.) in every possible world. In other words, if such a being exists, it exists necessarily and cannot fail to exist.
(P2) If it is possible that a maximally great being exists, then a maximally great being exists in some possible world. In modal logic, "possibly exists" means "exists in at least one possible world" (a complete way reality could have been).
(P3) If a maximally great being exists in some possible world, then it exists in every possible world. By definition, a maximally great being has necessary existence. If such a being exists in any possible world, it must exist in all possible worlds (it cannot be "contingent").
(P4) If a maximally great being exists in every possible world, then it exists in the actual world. The actual world is one of the possible worlds. If a being exists in every possible world, it exists in this one too.
(P5) If a maximally great being exists in the actual world, then a maximally great being exists. If such a being exists in our world, then it simply exists...God is real.
(C1) Therefore, a maximally great being exists.
Five Ways
First Way – From Motion/Change
(P1) Things in the world are in motion (undergoing change). By “motion,” Aquinas means change in a broad sense (e.g., from potential to actual): local motion, growth, decay, heating, cooling, etc. Our everyday experience and all of natural science presuppose that real change occurs.
(P2) Whatever is moved (changed) is moved by another. A thing cannot be actually changing in respect of some feature while remaining purely potential in that same respect, all by itself. For example, a piece of wood does not go from cold to hot by itself; it is heated by something already hot. Change from potentiality to actuality requires something already actual as its cause.
(P3) There cannot be an infinite regress of essentially ordered movers (causes of motion). In a here-and-now (essential) causal series...like a hand moving a stick moving a stone...the intermediate movers have causal power only by being moved/actualized by something prior in the series. If there were no first actualizer in such a series, there would be no motion at all, just as a train of cars cannot move without some engine.
(C1) Therefore, there exists a first unmoved mover: something that causes motion (change) in others without itself being moved (changed) by another in the same way.
(C2) This first unmoved mover is what we call God.
Second Way – From Efficient Cause
(P1) In the world of sense, we find an order of efficient causes. By an “efficient cause,” Aquinas means that which brings something into being or sustains it (e.g., a builder causing a house, fire causing heat, parents causing a child). Our experience and all of science presuppose that things have causes.
(P2) Nothing can be the efficient cause of itself. If something caused itself to exist, it would have to exist before it existed, which is impossible. A cause must be distinct from its effect at least in the order of explanation: the effect depends on the cause, not vice versa.
(P3) There cannot be an infinite regress of essentially ordered efficient causes. In an essentially ordered series of causes (here-and-now dependence), intermediate causes have causal power only because they receive it from prior causes. If there were no first cause in such a series, there would be no causal activity at all, like a series of gears with no primary driving gear.
(C1) Therefore, there must be a first efficient cause that is not itself caused by anything else.
(C2) This first uncaused cause is what we call God.
Third Way – From Contingency
(P1) There are contingent beings in the world...things that can exist and can fail to exist. A contingent being is one that does not have to exist; it begins to exist and can cease to exist (e.g., people, animals, stars, planets). We observe that such things come into being and pass away, and so their existence is not necessary.
(P2) If everything were contingent, then at some time nothing would have existed. If every being could fail to exist, then there is no guarantee that something or other would always exist. Given enough “time” or possibilities, there would be a state of affairs in which nothing at all existed.
(P3) If at some time nothing existed, then nothing would exist now. From absolute nothingness, nothing comes. If there were ever a total absence of being, nothing could begin to exist, because there would be nothing with the power to bring anything into existence.
(P4) But something does exist now (including ourselves and the world around us). Our present existence is undeniable. It follows that it cannot be the case that only contingent beings have ever existed.
(C1) Therefore, not all beings are contingent; there must exist at least one necessary being that cannot fail to exist.
(P5) A necessary being either has the cause of its necessity in itself or from another. Either the necessary being’s existence is explained by its own nature (it exists “of itself”), or it is necessary because something else makes it so.
(P6) There cannot be an infinite regress of necessary beings whose necessity is caused by another. An endless chain of beings whose necessary existence is borrowed from earlier beings would never explain why there is any necessary existence at all. There must be a necessary being that has the cause of its necessity in itself and does not derive it from another.
(C2) Therefore, there exists a necessary being that has its necessity in itself and is the cause of the existence of all contingent beings.
(C3) This necessary being is what we call God.
Fourth Way – From Degrees of Perfection
(P1) Among things, we find degrees of perfection (more or less good, true, noble, etc.). We naturally compare things in terms of value and excellence: some actions are better than others; some people are wiser, more just, or more loving than others; some beings have fuller reality or goodness than others (e.g., a rational person vs. a rock).
(P2) Degrees of a quality (like goodness or truth) are understood by comparison to a maximum or standard of that quality. When we say one thing is “hotter” or “colder,” “truer” or “better,” we implicitly measure it against some maximum or fullest instance. Aquinas (drawing on Aristotle) holds that gradations in a transcendental property (goodness, truth, nobility) imply a reference to something that possesses that property fully or maximally.
(P3) Therefore, if there are degrees of goodness, truth, and nobility in things, there must be something that is maximally good, maximally true, and maximally noble. This “maximum” is not just a useful fiction or idealization, but a real standard in terms of which all lesser participations in goodness and truth are measured and made intelligible.
(P4) What is maximally true and good is the cause of all that is true and good in other things. Aquinas argues that in any genus, the maximum is the cause of the others in that genus (e.g., the hottest thing is the cause of heat in other things). By analogy, the supreme source of goodness and truth causes and sustains all finite instances of goodness and truth.
(C1) Therefore, there exists something that is the maximum and source of all perfections such as goodness, truth, and nobility in things.
(C2) This maximally perfect being is what we call God.
Fifth Way – From Finality / Teleology
(P1) Non-rational things in nature regularly act for an end (toward goals or purposes). Aquinas notes that natural objects and processes...like acorns becoming oak trees, hearts pumping blood, planets following stable paths, and physical laws yielding orderly outcomes...consistently behave in ways that tend toward certain effects rather than others. They exhibit regular, goal-directed behavior.
(P2) Whatever lacks knowledge cannot direct itself to an end unless it is directed by something with knowledge and intelligence. An arrow does not fly toward a target by itself; it is aimed by an archer. Likewise, entities that have no awareness or understanding (e.g., physical particles, plants, organs) cannot by themselves “aim” at ends. Their consistent tendency toward certain outcomes calls for explanation in terms of an ordering intelligence.
(C1) Therefore, natural things that lack knowledge and yet act for an end must be directed by some being endowed with knowledge and intelligence.
(C2) This intelligent director of nature is what we call God.