Those who invalidate reason, ought seriously to consider, 'whether they argue against reason, with or without reason; if with reason, then they establish the principle, that they are laboring to dethrone;' but if they argue without reason, (which, in order to be consistent with themselves, they must do,) they are out of the reach of rational conviction, nor do they deserve a rational argument.

Reason spoiled, marred, or robbed of its perfection, ceaseth to be rational, and should not be called reason; inasmuch as it is premised to be depraved, or degenerated from a rational nature; and in consequence of the deprivation of its nature, should also be deprived of its name, and called subterfuge, or some such like name, which might better define its real character. Those who invalidate reason, ought seriously to consider, "whether they argue against reason, with or without reason; if with reason, then they establish the principle, that they are laboring to dethrone;" but if they argue without reason, (which, in order to be consistent with themselves, they must do,) they are out of the reach of rational conviction, nor do they deserve a rational argument.

To argue with a man who has renounced the use and authority of reason, and whose philosophy consists in holding humanity in contempt, is like administering medicine to the dead, or endeavoring to convert an atheist by scripture.

Reason can be fought with reason. How are you going to fight the unreasonable? The trouble with you, my dear, and with most people, is that you don’t have sufficient respect for the senseless. The senseless is the major factor in our lives. You have no chance if it is your enemy.

Reason is not one tool of thought among many, it is the entire toolbox. To advocate that reason be discarded in some circumstances is to advocate that thinking be discarded—which leaves one in the position of attempting to do a job after throwing away the required instrument.

...[W]e must not let it enter our minds that there may be no validity in argument. On the contrary we should recognize that we ourselves are still intellectual invalids; but that we must brace ourselves and do our best to become healthy... No greater misfortune could happen to anyone than that of developing a dislike for argument.

If we submit everything to reason our religion will be left with nothing mysterious or supernatural. If we offend the principles of reason our religion will be absurd and ridiculous . . . There are two equally dangerous extremes: to exclude reason, to admit nothing but reason.

To believe that any action based on an ignorance of fact can possibly succeed, is to abandon the use of reason.

to argue according to rigorous rational criteria is to guarantee that the results attained are universally valid.

"Unfortunately, the combatants on both sides keep arguing whether the modern mind is harmed - some say victimized - by "too much reason," the attackers holding that science and numbers are not the only truth; the defenders retorting that if reason is given up, intellectual anarchy and wild superstition will reign. The latter are right about reason as an activity - reasoning; the former are right about Rationalism, the dominance of a particular form of reason and its encroachment where it does not belong."

Trying to win an argument with an irrational person is like trying to teach a cat to snorkel by providing written instructions. No matter how clear your instructions, it won't work. Your best strategy is to reduce the time you spend in that sort of situation.

There is nothing so consistent with reason as this denial of reason.

Two people feel strongly about an issue, their feelings come first, and their reasons are invented on the fly, to throw at each other. When you refute a person’s argument, does she generally change her mind and agree with you? Of course not, because the argument you defeated was not the cause of her position; it was made up after the judgment was already made.

He who establishes his argument by noise and command, shows that his reason is weak.