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Thinking Rationally: A Biblical Perspective

Everyone thinks. This is what makes us distinctly human (cf. Jude 10, ESV).

But sometimes, when we perceive that a person has made an egregious error, we are fond of interjecting: "You just need to think!" In reality, it was probably thinking that messed them up in the first place.

The truth is, errors do not usually come from people who fail to think, but from people who succeed in thinking poorly.

Poor thinking involves the abuse of reason (man's intellectual means of drawing correct conclusions by gathering relevant data), which may take many forms.

Some are inclined to place too much emphasis upon their native intellectual faculties (rationalism); others prefer to de-emphasize (or reject entirely) the use of reason in their lives (subjectivism).

Before evaluating the proper use of reason, it is advantageous first to consider its abuses in greater detail.


Rationalism embraces an over-emphasis of reason. It posits that man, unaided by supernatural revelation, may use his mind alone to resolve all of his quandaries and determine his own fate.

From the rationalist point of view, natural reason will always trump arbitrary revelation (i.e., religion). No amount of historical, legal, or empirical evidence (Biblical or otherwise) will ever amend the rationalist's thinking on ideas he has reached by reason.

Hence, rather than esteeming reason as one of the legitimate means of discovering truth, the rationalist believes that all truth is determined by reason — that reason is "the unique path to knowledge" (Audi, 771).

There are some rationalists who attach themselves to Christian theology, many of whom do not realize their own rationalistic bent. Any person who endeavors to mitigate, reject, amend, or cherry-pick the will of the Lord so as to suit their natural knowledge is a rationalist.

The contemporaries of Jeremiah denied the Lord's warning of impending destruction and enslavement (cf. Jer. 6.14; 7.4; 8.8-13). They followed the "counsels...of their evil hearts" instead of the word of the Lord (cf. Jer. 7.24; 14.13-16). Rationality (e.g., "peace, peace..." and, "the temple of the Lord!") had stifled out faith in God's revelation.

So, today, on the same basis, many deny the historicity of the miracles of the Bible (cf. Jn. 20.30-31); others deny the reality of "hell" (cf. Lk. 12.5); some believe that worship and service to God have no fixed pattern to which all must conform (cf. Jn. 4.20-24; 2 Tim. 1.13); others suggest that baptism bears no connection whatsoever to the soul's salvation (cf. Mk. 16.16; 1 Peter 3.21).

Each of these errors take their origin from rationalism — that reason, not faith, ultimately must determine all truth. Since native reason, of itself, contains no information about these and other controversial subjects, they are cast aside with feckless bravado.

Rational Christians, on the other hand, must recognize a power higher than logic (not antithetical to logic). As Edward Carnell suggests:

"For the Christian, God, not logic, is the ultimate reason for things, for God is the author of logic itself" (39).

Indeed, God transcends all of his creations, for everything, including logic, exists from him, through him, and for him (cf. Rm. 11.33-36).


Subjectivism embraces a mitigation or rejection of reason altogether.

Whereas the rationalist accepts certain propositions as objective and universal, the subjectivist proclaims that truth resides solely in the heart of the individual. Thus, truth is what you want it to be. Part and parcel of this philosophy is the notion that truth cannot be proven objectively.

Most of those who claim association with Christianity today have embraced the core of subjectivism. Hence, religious people will declare: 'God cannot be proven; he must be experienced.' We hear expressions like: "better-felt-than-told;" or, "deeds, not words," etc. These spiritual subjectivists staunchly oppose the use of reason in their spiritual lives. After all, without argument and reason there would be no division and strife — we would all just get along!

Interestingly, by taking this position, subjectivists have committed at least two self-contradictions:

(1) they have reasoned that it is wrong to reason; and

(2) they have taken a dissenting viewpoint from others, thus creating a division in religious thinking.

Any belief which must deny itself in the process of expressing itself is a belief that cannot be trusted.

Our Lord was by no means a subjectivist. He said, "everyone that is of the truth hears my voice" (John 18.38). He is the universal standard for truth. He required men to worship God according to "truth" (Jn. 4.24), and specifically condemned those who worship by "laying aside the commandment of God" in order to "keep" their own self-determined "tradition" (cf. Mk. 7.6-9).

Neither was Jesus, the logos of God (Jn. 1.1), opposed to the use of reason (argument) and logic (principles of validity). According to him, the greatest commandment of God involves the proper use of the mind (cf. Mt. 22.36-37). To combat the false teachers of his day, Jesus appealed to the Scriptures, logic, and the original langauge/grammar of the text (cf. Mt. 22.23-33, 41-45).

Too, the reality of God is a thing that may be "clearly seen" by observing and reflecting upon the operations of nature, provided the mind ("being understood...") is put to work properly (Rom. 1.20).

Paul frequently "reasoned in the synagogue with the Jews and with the Gentile worshippers" (cf. Act 17.2, 17; 18.4, 19; 24.25), the sense being that he attempted to persuade them through Scriptural argument and discourse.

It is in this sense, too, that God appealed to the Israelites through Isaiah: "Come, now, and let us reason together" (1.18) — that is, let us discuss the case together. God does not want the heart without the mind of man. We are instructed to

"be transformed by the renewing of your mind" to be "acceptable to God, which is your reasonable service" (Rom. 12.2).

"Reasonable" translates the word, logikos. In other words, we do not serve God by base compulsion, or on a spontaneous, subjective whim. Rather, let our service to God be intellectual and deliberate, with clear mental purpose and planning. The present-day "spontaneous worship" craze, rooted in subjectivism, has no support with God.

To recap: the rationalist exalts the rational mind of man over the arbitrary will of the Lord (Proverbs 3.5; cf. 2 Cor. 10.5). The subjectivist exalts the arbitrary will of man over the rational mind of the Lord (cf. Proverbs 28.26; Jer. 17.5-10). Neither are appropriate.

The Proper Use of Reason

Followers of Christ recognize that the Scriptures are not the product of the reason of man (cf. 1 Cor. 1.20-21), nor yet the subjective impulses of human authors (cf. 2 Peter 1.20-21). They are, "in truth, the word of God" (1 Thess. 2.13).

Further, the truth is not, as Platonic Idealism suggests, a thing remembered, which is simply lying dormant in every human mind (see Ozman, 16). The truth of Christ is, rather, a thing revealed (Gal. 3.23; Eph. 3.5), a "secret" which had to be told by our Creator through his prophets (Rm. 16.25). This revealed truth is universally applicable in its force, contrary to subjectivism (for more on these thoughts, see: "Faith, Reason, & Subjectivity") .

But, since logic derives from God, it is our task to uncover it and then use it properly to know God and understand his revealed will (cf. Jn. 7.24; 2 Tim. 2.15c). As Geisler and Brooks observe:

"A rationalist tries to determine all truth by reason. Reasonable Christians only try to discover it" (18).

Thus, we must attend ourselves to the proper use of reason, by observing the elemental principles of logic.

The study of logic embraces at least four fundamental and axiomatic laws. They are as follows:

(1) The law of non-contradiction (A is not non-A): no two contradictory statements can be true at the same time and in the same sense.

One medieval philosopher, in commenting about this law, humorously wrote:

"Anyone who denies the law of non-contradiction should be beaten and burned until he admits that to be beaten is not the same as not to be beaten, and to be burned is not the same as not to be burned" (Avicenna).

Indeed, truth, in order to be truth, must not contradict. Inconsistency is the progeny of falsehood — not truth.

There are some who suggest that non-Christians are not amenable to the marriage laws of Christ (contrary to Mt. 19.9, "whoever"). Thus, though non-Christians may seem to marry, they are not actually married, and are therefore not confined to the principles of monogamy and fidelity which marriage requires (contrary to Heb. 13.4, "among all"). They may, in other words, marry at will.

However, it is suggested that Christians are amenable to such laws. Accordingly, non-Christians do not truly marry, whereas Christians do. But observe this: the union between a Christian and a non-Christian is itself permissible (cf. 1 Cor. 7.13-14; 1 Peter 3.1). But if Christians may truly marry while non-Christians may not, the union between a Christian and a non-Christian is both a marriage and not a marriage at the same time! The Christian is married to the non-Christian (since marriage applies to the Christian), but the non-Christian is not married to the Christian (since marriage does not allegedly apply to the non-Christian). This position demands a logical absurdity. It cannot logically be true, since it violates the law of non-contradiction.

(2) The law of identity (A is A): an object is the same as itself.

Not long ago, a gentlemen held a petition in Berkley, California to ratify a law that stated: "every entity shall be identical to itself." Any entity caught being un-identical to itself was subject to a fine of up to one tenth of a cent! According to the San Francisco Chronicle, the law didn't pass.

The Lord articulated the law of identity to Moses at the burning bush. He said: "I am who I am" (Ex. 3.14). He is objective reality — eternal existence. He is not non-existence, for that opposes the law of identity.

Even so, there are many who, seeking to redefine the meaning of various words to suit their particular dogma or tradition, are unwittingly violating the law of identity in their conviction and practice. In John Calvin's famous work, Institutes of the Christian Religion, the theologian attempted an explanation of the mode of baptism.

“Whether the person baptized is to be wholly immersed . . .or whether he is only to be sprinkled with water, is not of the least consequence: churches should be at liberty to adopt either, according to the diversity of climates, although it is evident that the term, baptize, means to immerse, and that this was the form used by the primitive Church” (524).

Calvin admits that baptism is immersion, but allows baptism to be sprinkling or pouring too. This, quite frankly, is a contradiction of terms. As Calvin correctly observes, baptism is a burial, which symbolizes the burial (and subsequent resurrection) of Christ (cf. Rm. 6.1-4; Col. 2.12). This was its consistent meaning throughout the ancient world. Thus, Euripides spoke of baptizing a pitcher, plunging it into the sea, so as to draw salt-water (Hecuba, 610). Baptism can no more be sprinkling than a circle can be a square. If I had a tenth of a cent for every time the law of identity has been infringed, I likely would be very wealthy indeed.

(3) The law of excluded middle (either A or non-A): a thing either is or is not.

Many believe Jesus was a good and wise man — but nothing more. In their estimation, he was not the long-predicted messiah, never mind being "God with us" (Mt. 1.23). But can these ideas be logically reconciled? The law of excluded middle insists that they cannot. Consider:

To the woman at Jacob's well, Jesus claimed to be the long-anticipated messiah (Jn. 4.25-26; cf. Mt. 16.16-17; Jn. 11.27). He further assumed the right to forgive sins, a power which God alone possesses (cf. Mk. 2.5-12; Lk. 7.48-50; Isa. 43.25). When Thomas confessed to Jesus, "my Lord and my God," Jesus congratulated both Thomas and all others who acknowledge this truth (Jn. 20.28-29; cf. Heb. 1.6).

In this instance, the law of excluded middle requires either that (1) Jesus spoke truly; or (2) Jesus spoke falsely. If Jesus spoke truly, then Jesus was more than just a good, wise man — he was the divine messiah. If, however, Jesus spoke falsely, either (1) he knew he spoke falsely; or (2) he did not know he spoke falsely. If he knew he spoke falsely, then he was a charlatan and a liar. If he did not know he spoke falsely, yet claimed to be the eternal God, then he was deranged and foolish. Either way, if Jesus is anything less or other than what he claimed to be, he should not be eulogized; he should be denounced. As C.S. Lewis remarked:

"A man who was just a man and said the sort of things Jesus said would not be a great or honest teacher. He would be either an insane man on a level with the man who says he is a boiled egg or the Evil One of Hell. You must choose. Either this man was, and is, the Son of God: or an insane man or something worse" (40-41).

Philip Schaff observes:

"The wisdom of Jesus is clear as the sky, fresh as the mountain air, sharp and cutting as a knife, completely healthy and alive, always ready and always calm. Could the mind of Christ think up such a wild lie about his own character and mission? That is senseless imagination" (97)!

Thus, either praise him as the divine messiah, or malign him as a senseless knave. The law of excluded middle allows for no middle ground (cf. Jn. 8.23-24; Mt. 6.24; Rev. 3.15-16) — see the footnote ± of the article, "Our Mistaken Master," for an expansive treatment of this argument .

(4) The law of rational inference: draw only such conclusions as are warranted by the evidence.

There are many erroneous ideas when it comes to the issue of inference and implication. Studying this from a Biblical perspective may prove quite constructive.

First, some assume that inference and implication are transposable synonyms, whereas they are not. An implication — a message suggested indirectly — is performed by a speaker or one who is communicating a message. However, an inference — a conclusion drawn from evidence — is performed exclusively by a listener or one who is receiving the message thus given. Hence, the Bible may imply, but it is the duty of the student to infer the implication from the explicit message(s).

Second, not all inferences are essential or absolute. Some inferences may have a high degree of plausibility and yet not be certain. These are based upon relative assumptions.

When Nathanael wondered whether "any good thing can come out of Nazareth" (Jn. 1.46), he was drawing a relative inference. Since Nazareth, a relatively obscure and insignificant town, had developed an opprobrious reputation, it became common to suppose that individuals who hail from that city were similarly disreputable. Thus, since nothing good tends to come from Nazareth, and since Jesus came from Nazareth, it was likely to suppose that Jesus was also not good.

In spite of the plausibility of this reasoning, Nathanael acknowledged that it was not an essential conclusion, and kept an open mind regarding Jesus. Accordingly, an inference may be plausible — and even likely — but not necessary in all cases.

Third, whereas some mistakenly assume that every inference is absolute in veracity, others more egregiously allege that inferences are never absolute — that they are always based upon mere probabilities and, therefore, can never be affirmed with any degree of certainty. Neither extreme will due.

There are many Biblical passages that affirm by implication — implications which we must infer, but which are no less true, given the accuracy of the Biblical record. In Matthew 22.23-32, the Sadducees, who denied the concept of life after death (i.e., the resurrection, Acts 23.8), came to Jesus with the intent of criticizing the teachings and integrity of Jesus. The Lord responded, "Ye do err, not knowing the Scriptures" (v. 29). Then, to prove that the Law of Moses taught the doctrine of life after death, he said this:

"have you not read what was spoken to you by God, saying, 'I am the God of Abraham, the God of Isaac, and the God of Jacob'? God is not the God of the dead, but of the living" (vv. 31-32).

The passage does not explicitly teach the doctrine of the resurrection, but Jesus was affirming that this Scripture necessarily implies it. The present tense of the text indicated a current reality — I am the God of Abraham, etc. He did not say, I was the God of Abraham, as though in the past, implying that Abraham is no more; nor did he say, I shall be the God of Abraham, as though in the future, implying that Abraham will one day be alive, though he is now non-existent; but I am. Abraham, Isaac, and Jacob were then living, even though they had been "dead" for hundreds of years. Therefore, Abraham must be experiencing life after death. Even though that affirmation was not expressly stated in the text, it was stated nonetheless. It was not mere guesswork or probability.

Furthermore, when the four kings from the east overtook the five kings of the plain of Jordan, the Bible says that they took Lot, who then lived in Sodom. It mentions the capture of Lot, but no others (Gen. 14.12). Yet, later we are told that Abraham "brought back his brother Lot and his goods, as well as the women and the people" (14.16). We must infer that the women and the people were captured too, for, though not explicitly stated, that is what the data implies.

The law of rational inference may be used to demonstrate the error of infant baptism. Since the Scriptures require belief, repentance, and confession before valid baptism (cf. Mk. 16.16; Acts 2.38; Rom. 10.10), and since infants cannot believe, repent, or confess (cf. Isaiah 7.16; Heb. 5.13; 1 Cor. 3.1f; Mt. 11.25), it necessarily follows that no infant baptism will be valid. Too, since baptism is for the purpose of washing away sins and entering into the kingdom (cf. Acts 22.16; 2.38; Jn. 3.3-5), and since infants have committed no sins to wash away, and are already spiritually alive in the kingdom (cf. 1 Cor. 14.20; Mt. 19.4; see also Romans 7.9), infant baptism is unwarranted. Sectarian infant baptism is logically fallacious.


Being a Christian demands learning to reason properly. In religion especially, poor thinking is a most insidious menace. It is a sobering truth to realize that the use of rational thinking can make the difference between a soul being saved and a soul being lost (cf. Rm. 1.20f; Acts 17.29-31).

Let us, then, ever "handle aright the word of truth" (2 Tim. 2.15) by thinking — and doing so rationally.

Audi, Robert.  The Cambridge Dictionary of Philosophy.  Cambridge University Press: Cambridge, UK, 1995. 2nd edition, 1999.

Avicenna.  Metaphysics, I; commenting on Aristotle, Topics I.11.105a4-5.

Calvin, John.  Institutes of the Christian Religion (Two Volumes).  Grand Rapids: Wm. B. Eerdmans, Vol. II, 1975.

Carnell, Edward.  An Introduction to Christian Apologetics: A Philosophic Defense of the Trinitarian-Theistic Faith.  Grand Rapids, MI: Wm. B. Eerdmans Publishing Company, 1973.

Geisler, Norman L. and Ronald M. Brooks. Come, Let Us Reason: An Introduction to Logical Thinking.  Grand Rapids, MI: Baker Book House, 2006.

Lewis, C.S.  Mere Christianity.  New York: The MacMillan Company, 1960.

Liddell, Henry and Robert Scott.  A Greek-English Lexicon.  Oxford: Clarendon Press, 1940.

Ozman, Howard and Samuel Craver.  Philosophical Foundations of Education.  Pearson Education, Inc.: 2003, 7th edition.

Ruby, Lionel.  Logic: An Introduction.  Paper Tiger, Inc., 2000.

Schaff, Philip.  The Person of Christ.  New York: American Tract Society, 1913.

Vine, W.E.  Vine's Complete Expository Dictionary of Old and New Testament Words.  Nashville, TN: Thomas Nelson, Inc., 1985.

Warren, Thomas B.  Logic and the Bible.  National Christian Press, Inc., 1982.

Wilson, Douglas J. and James B. Nance.  Introductory Logic.  Canon Press, 2006.


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