Aquinas’ Five Ways
In the first part of his Summa Theologica, Thomas Aquinas developed his five arguments for God’s existence. These arguments are grounded in an Aristotelianontology and make use of the infinite regression argument. Aquinas did not intend to fully prove the existence of God as he is orthodoxly conceived (with all of his traditional attributes), but proposed his Five Ways as a first stage, which he built upon later in his work. Aquinas’ Five Ways argued from the unmoved mover, first cause, necessary being, argument from degree, and the teleological argument.
- The unmoved mover argument asserts that, from our experience of motion in the universe (motion being the transition from potentiality to actuality) we can see that there must have been an initial mover. Aquinas argued that whatever is in motion must be put in motion by another thing, so there must be an unmoved mover.
- Aquinas’ argument from first cause started with the premise that it is impossible for a being to cause itself (because it would have to exist before it caused itself) and that it is impossible for there to be an infinite chain of causes, which would result in infinite regress. Therefore, there must be a first cause, itself uncaused.
- The argument from necessary being asserts that all beings are contingent, meaning that it is possible for them not to exist. Aquinas argued that if everything can possibly not exist, there must have been a time when nothing existed; as things exist now, there must exist a being with necessary existence, regarded as God.
- Aquinas argued from degree, considering the occurrence of degrees of goodness. He believed that things which are called good, must be called good in relation to a standard of good—a maximum. There must be a maximum goodness that which causes all goodness.
- The teleological argument asserts the view that things without intelligence are ordered towards a purpose. Aquinas argued that unintelligent objects cannot be ordered unless they are done so by an intelligent being, which means that there must be an intelligent being to move objects to their ends: God.
The ontological argument has been formulated by philosophers including St. Anselm and René Descartes. The argument proposes that God’s existence is self-evident. The logic, depending on the formulation, reads roughly as follows:
- God is the greatest conceivable being.
- It is greater to exist than not to exist.
- Therefore, God exists.
Thomas Aquinas criticized the argument for proposing a definition of God which, if God is transcendent, should be impossible for humans. Immanuel Kant criticized the proof from a logical standpoint: he stated that the term “God” really signifies two different terms: both idea of God, and God. Kant concluded that the proof is equivocation, based on the ambiguity of the word God. Kant also challenged the argument’s assumption that existence is a predicate (of perfection) because it does not add anything to the essence of a being.
If existence is not a predicate, then it is not necessarily true that the greatest possible being exists. A common rebuttal to Kant’s critique is that, although “existence” does add something to both the concept and the reality of God, the concept would be vastly different if its referent was an unreal Being. Another response to Kant is attributed to Alvin Plantinga who explains that even if one were to grant Kant that “existence” is not a real predicate, “Necessary Existence”, which is the correct formulation of an understanding of God, is a real predicate, thus according to Plantinga Kant’s argument is refuted.
These two arguments follow from possible deductions, i.e., they can be set up as deductions and therefore are placed here.
- Argument from Meaning.
- Argument from Ethics, being one type of view by ontologically considered intelligence.
Inductive arguments argue their conclusions through inductive reasoning.
- Another class of philosophers asserts that the proofs for the existence of God present a fairly large probability though not absolute certainty. A number of obscure points, they say, always remain; an act of faith is required to dismiss these difficulties. This view is maintained, among others, by the Scottish statesman Arthur Balfour in his book The Foundations of Belief (1895). The opinions set forth in this work were adopted in France by Ferdinand Brunetière, the editor of the Revue des deux Mondes. Many orthodox Protestants express themselves in the same manner, as, for instance, Dr. E. Dennert, President of the Kepler Society, in his work Ist Gott tot? The will to believe doctrine was pragmatist philosopher William James‘ attempt to prove God by showing that the adoption of theism as a hypothesis “works” in a believer’s life. This doctrine depended heavily on James’ pragmatic theory of truth where beliefs are proven by how they work when adopted rather than by proofs before they are believed (a form of the hypothetico-deductive method).
- The argument from reason holds that if, as thoroughgoing naturalism entails, all human thoughts are the effect of a physical cause, then there is no reason for assuming that they are also the consequent of a reasonable ground. Knowledge, however, is apprehended by reasoning from ground to consequent. Therefore, if naturalism were true, there would be no way of knowing it—or anything else not the direct result of a physical cause—and one could not even suppose it, except by a fluke.
- The anthropic argument suggests that basic facts, such as humanity’s existence, are best explained by the existence of God.
- Qualia-based arguments: Some philosophers see the existence of Qualia (or the hard problem of consciousness) as strong arguments against materialism and therefore for the existence of material and immaterial entities.
- The teleological argument argues that the universe’s order and complexity are best explained by reference to a creator God. It starts with a rather more complicated claim about the world, i.e. that it exhibits order and design. This argument has two versions: One based on the analogy of design and designer, the other arguing that goals can only occur in minds.
- The hypothesis of Intelligent design proposes that certain features of the universe and of living things are the product of an intelligentcause. Its proponents are mainly Christians.
- Arguments that a non-physical quality observed in the universe is of fundamental importance and not an epiphenomenon, such as Morality (Argument from morality), Beauty (Argument from beauty), Love (Argument from love), or religious experience (Argument from religious experience), are arguments for theism as against materialism.
- The transcendental argument suggests that logic, science, ethics, and other serious matters do not make sense in the absence of God, and that atheistic arguments must ultimately refute themselves if pressed with rigorous consistency.
- The argument from degree, a version of the transcendental argument posited by Aquinas, states that there must exist a being which possesses all properties to the maximum possible degree in order for such properties to be coherent.
- Argument from belief in God being properly basic as presented by Alvin Plantinga.
- Argument from the confluence of proper function and reliability and the evolutionary argument against naturalism, which demonstrate how naturalism is incapable of providing humans with the cognitive aparatus necessary for their knowledge to have positive epistemic status.
- Argument from Personal Identity.
- Argument from the “divine attributes of scientific law”.
Arguments from historical events or personages
- Christianity and Judaism assert that God intervened in key specific moments in history, especially at the Exodus and the giving of the Ten Commandments in front of all the tribes of Israel, positing an argument from empirical evidence stemming from sheer number of witnesses, thus demonstrating his existence.
- The argument from the Resurrection of Jesus. This asserts that there is sufficient historical evidence for Jesus’s resurrection to support his claim to be the son of God and indicates, a fortiori, God’s existence. This is one of several arguments known as the Christological argument.
- Islam asserts that the revelation of its holy book, the Qur’an, vindicates its divine authorship, and thus the existence of God.
- The Church of Jesus Christ of Latter-day Saints, also known as Mormonism, similarly asserts that the miraculous appearance of God, Jesus Christ, and angels to Joseph Smith and others and subsequent finding and translation of the Book of Mormon establishes the existence of God. The whole Latter Day Saint movement makes the same claim for example Community of Christ, Church of Christ (Temple Lot), Church of Jesus Christ (Bickertonite), Church of Jesus Christ of Latter Day Saints (Strangite), Church of Jesus Christ (Cutlerite), etc.
- The Church of Jesus Christ of Latter Day Saints (Strangite), similarly asserts that the finding and translation of the Plates of Laban, also known as the Brass Plates, into the Book of the Law of the Lord and Voree plates by James Strang, One Mighty and Strong, establishes the existence of God.
- Various sects that have broken from the Church of Christ (Temple Lot) (such as Church of Christ “With the Elijah Message” and Church of Christ (Assured Way)) claim that the message brought by John the Baptist, One Mighty and Strong, to Otto Fetting and W. A. Draves in The Word of the Lord Brought to Mankind by an Angel establishes the existence of God.
Arguments from testimony
Arguments from testimony rely on the testimony or experience of witnesses, possibly embodying the propositions of a specific revealed religion. Swinburne argues that it is a principle of rationality that one should accept testimony unless there are strong reasons for not doing so.
- The witness argument gives credibility to personal witnesses, contemporary and throughout the ages. A variation of this is the argument from miracles (also referred to as “the priest stories”) which relies on testimony of supernatural events to establish the existence of God.
- The majority argument argues that the theism of people throughout most of recorded history and in many different places provides prima facie demonstration of God’s existence.