Short answer: probably not. But that doesn’t mean there aren’t ways in which to determine with a high degree of probability whether or not God exists. Many have tried to articulate various arguments believed to be decisive in demonstrating that “God” exists, none more famous than the so-called “Five Ways” of Thomas Aquinas. Thomas died in 1274, just shy of his fiftieth birthday.

The Five Ways include:

• The argument from motion or change
• The argument from causation
• The argument from contingency of being
• The argument from gradation
• The argument from design

Here is a brief summary of each argument taken directly from Thomas himself.

(1) Consider the following, taken from his first argument from motion or change:

“The first and most obvious proof is that which is based on change. It is certain and evident to the senses that some things in this world are in a process of change. But anything in a process of change is being changed by something else. For although things which are changing possess the potential for [the actuality] towards which they move, they do not yet have it, whereas that which causes the change possesses it in actuality. To cause change is nothing more than to transform potentiality into actuality, but to transform potentiality into actuality can only be done by something in which the actuality already exists. For example, fire, which is hot in actuality, causes wood, which is hot in potentiality, to become hot in actuality, and thereby it brings about a change in the nature of the wood. Now it is impossible for something to be actually and potentially the same thing at the same time. It may, however, be actually one thing and potentially something else. For example, something which is actually hot cannot be potentially hot at the same time. It can, however, be potentially cold. So it follows from this that something which is changing cannot itself be the cause of the change and the result of the change at the same time: a thing cannot change itself. Anything that is changing, therefore, is being changed by something else. But if the thing that is causing the change is itself being changed, it is itself being changed by a second something, and this, in turn, by a third. But we cannot go on forever with this process, for if we do, there will be no First Changer to cause the first change and therefore no subsequent causes [to cause the subsequent changes]. A second cause will not produce change unless it is acted upon by a first cause. A stick, for example, will not move or change anything else unless it is itself first moved by the hand. It follows, therefore, that one is bound to arrive at some first cause of change which is not itself changed by anything, and this is what everybody understands by God” (Summa Theologica, Part I, Question Two, Article Three).

(2) Aquinas appeals, secondly, to the nature of an efficient cause:

“We find that there is a sequence of efficient causes in sensible things. But we do not find that anything is the efficient cause of itself. Nor is this possible, for the thing would then be prior to itself, which is impossible. But neither can the sequence of efficient causes be infinite, for in every sequence the first efficient cause is the cause of an intermediate cause, and an intermediate cause is the cause of the ultimate cause, whether the intermediate causes be many, or only one. Now if a cause is removed, its effect is removed. Hence if there were no first efficient cause, there would be no ultimate cause, and no intermediate cause. But if the regress of efficient causes were infinite, there would be no first efficient cause. There would consequently be no ultimate effect, and no intermediate causes. But this is plainly false. We are therefore bound to suppose that there is a first efficient cause. And all men call this God” (ibid.).

(3) His third argument is based on the nature of possibility and necessity. He argues that whereas some things may either exist or not exist, there must be something that must exist:

“Now everything which is necessary either derives its necessity from elsewhere, or does not. But we cannot go on to infinity with necessary things which have a cause of their necessity, any more than with efficient causes, as we proved. We are therefore bound to suppose something necessary in itself, which does not owe its necessity to anything else, but which is the cause of the necessity of other things. And all men call this God” (ibid.).

(4) The fourth way of arguing for God’s existence is

“from the degrees that occur in things, which are found to be more and less good, true, noble, and so on. Things are said to be more and less because they approximate in different degrees to that which is greatest. A thing is the more hot the more it approximates to that which is hottest. There is therefore something which is the truest, the best, and the noblest, and which is consequently the greatest in being, since that which has the greatest truth is also greatest in being. . . . There is therefore something which is the cause of the being of all things that are, as well as of their goodness and their every perfection. This we call God” (ibid.).

(5) Fifth, and finally, Aquinas appeals to the fact that

“some things, like natural bodies, work for an end even though they have no knowledge. . . . Now things which have no knowledge tend towards an end only through the agency of something which knows and also understands, as an arrow through an archer. There is therefore an intelligent being by whom all natural things are directed to their end. This we call God” (ibid.).

All five “ways” of demonstrating God’s existence ultimately reduce to the cosmological argument, moving from an event or aspect of reality to what Aquinas insists must be its first and original Cause, namely, God.

Whether or not these arguments (or any others) are persuasive, one thing must be noted. The Apostle Paul declares in Romans 1:19-21 that God has made clear in the material creation, or what we call nature, that he exists, and that all mankind is without excuse for not worshiping him and giving him thanks. He writes:

“For what can be known about God is plain to them, because God has shown it to them. For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse. For although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened” (Rom. 1:19-21).

Truly, he is the “fool” who says in his heart, “There is no God” (Ps. 14:1).