The Limitations of the Mind — Its Consequences

Philosophers scatter their mental powers by addressing subjects that involve too many relationships and depend on too many factors, while following no order in their studies

Men fall into a vast number of errors not only because they occupy themselves with questions that border on the infinite—for their minds are not infinite—but also because they tackle subjects of immense scope, while their understanding is very limited.

We have already observed that just as a piece of wax cannot receive several distinct, well-defined shapes at the same time, so too the mind cannot hold many clear ideas at once; that is, it cannot perceive several things distinctly in a single moment. From this it easily follows that one should not begin by investigating hidden truths whose understanding depends on too many factors, some of which are unknown or insufficiently familiar to us. We must study in an orderly fashion, using what we already know clearly to learn what we do not know, or know only vaguely.

Yet most students pay no heed to this. They do not test their own abilities, nor do they reflect on how far their understanding can reach. It is secret vanity and an uncontrolled desire for knowledge—not reason—that guides their studies. Without consulting reason, they attempt to penetrate the most obscure and impenetrable truths, and to solve questions involving so many connections that even the sharpest and most penetrating mind could arrive at complete certainty only after centuries of work and an almost infinite number of experiments.

Medicine and ethics have many questions of this kind.

All sciences dealing with the details of bodies and their specific properties—such as those of animals, plants, and metals—can never be rendered certain especially if:

• they are not approached in a new way
• one does not begin with the simpler, more elementary sciences upon which they depend.

Yet students refuse to take the trouble to follow a systematic order in their inquiries.

They cannot agree on the certainty of physical principles; they admit themselves that they do not understand the general nature of bodies or their fundamental qualities. Even so, they imagine they can explain, for example, why the hair of old men turns white and their teeth grow black, and other similar questions that depend on so many causes that no certain explanation can ever be given.

To do so, one would need to know exactly what makes hair white in particular, the bodily fluids that nourish it, the internal filters that allow these fluids to pass, the structure of the hair roots and the skin through which they grow, and how all these things differ between a young person and an old man—something that is either impossible or at least extremely difficult to know.

Example drawn from Aristotle

Aristotle claimed to know the cause of graying hair in old age.

He offered several explanations.

But because of his natural inclination to explain everything, he did not stop there.

He went on to discover that the very same cause which turns hair white is also responsible for why some people and some horses have one blue eye and one eye of a different color. Here are his own words:

“Men and horses often have eyes of different colors for the same reason that a man’s hair turns gray.”

This is remarkable, but nothing seemed hidden from this great thinker.

He offers explanations for so many phenomena in nearly all his works on natural philosophy—phenomena that even the most learned minds of our time consider beyond understanding—that people have rightly said of him that he was given to us by God so that we might be ignorant of nothing that can be known.

“The doctrine of Aristotle is supreme truth, for his intellect represents the highest limit of human understanding. Hence it is rightly said that he was created and bestowed upon us by divine providence, so that we might not remain unaware of what it is possible to know.” Averroes even went so far as to say that divine providence gave us Aristotle to teach us what it is impossible to know.

For indeed, this philosopher does not only teach us what can be known; if we are to take him at his word—since his doctrine is supreme truth—he also teaches us what cannot possibly be known.

One must truly have great faith to accept Aristotle’s claims when he offers nothing but logical arguments and explains natural phenomena only through vague impressions derived from the senses—especially when he makes bold pronouncements on questions that do not seem capable of any human solution. And Aristotle himself takes special care to remind us that we must believe him on his authority; for he states it as an unassailable axiom that “the student must believe.”

Students are sometimes obliged to trust their teachers, but only concerning observed facts and experiences. If they wish to become true philosophers, they must examine the reasoning behind what they are taught and accept it only when they recognize its clarity through their own judgment. But to become a follower of Aristotle, one need only believe and memorize.

The same mental attitude required for reading history is sufficient for reading his philosophy; for if one dares to use one’s own mind and reason, one cannot hope to become a great philosopher—since, as he says, “the student must believe.”

Aristotle and so many other philosophers claimed to know what cannot be known is that they failed to distinguish properly between different kinds of knowledge—between having certain, evident understanding and having only a probable opinion.

They failed to make this distinction because the subjects they studied were always far more extensive than their own minds could grasp. As a result, they usually saw only parts of the whole, without being able to take everything into account at once. This is enough to arrive at many plausible ideas, but not enough to discover the truth with certainty.

They pursued knowledge only out of vanity—and because plausible opinions often win more admiration from others than does the truth itself, since they are better suited to the ordinary limits of human understanding—they neglected to seek the methods necessary to expand and strengthen the mind.

Thus they could never penetrate the deeper meaning of truths that are even slightly hidden.

By contrast, how geometers proceed correctly in the search for truth, especially those who use algebra and analysis

Only geometers have clearly recognized the narrow limits of the human mind; or at the very least, their method of study shows they understand this perfectly—especially those who use algebra and analysis, which Viète and Descartes have revived and perfected in our own time. This is evident in the fact that they never attempt to solve highly complex problems until they have fully mastered the simpler principles upon which those problems depend. They do not study curved lines such as conic sections until they have a firm command of basic geometry.

What is particularly characteristic of those who use analysis is that, recognizing the mind cannot focus on many figures at once—and cannot even easily visualize solids with more than three dimensions, even though it is often necessary to conceive of such things—they make use of ordinary letters, which are very familiar to us, to express and simplify their ideas. In this way, the mind is not overburdened or distracted by having to form images of multiple shapes and countless lines. It can grasp at a single glance what would otherwise be impossible to see; for when its capacity is well managed, the mind can penetrate far deeper and extend its reach to many more things.

Thus, as we shall explain elsewhere, the entire art of making the mind sharper and more expansive consists in properly managing its powers and limits—never wasting it on matters that are unnecessary for discovering the specific truth being sought. This is a point of great importance. For it clearly shows that the usual forms of logic are better suited to reduce the mind’s capacity than to increase it. If one tries to follow their rules in the search for truth, the mind’s attention is divided, leaving it with less power to focus and understand the full scope of the subject being examined.

Their method strengthens the mind, while Aristotle’s logic weakens it

From what has been said, it seems clear that most people have given little thought to the nature of the mind when they set out to seek knowledge. They have never fully accepted its limitations, nor understood the need to manage and even strengthen its capacity. This is one of the chief causes of their errors and of their lack of progress in their studies.

This is not to say that no one realizes their mind is limited and has only a narrow range. Everyone surely knows this, and everyone admits it—but most know it only vaguely and acknowledge it only in words. Their actual conduct in study contradicts their own admission; for they act as if they truly believed their minds had no bounds at all, and they attempt to investigate matters that depend on countless causes, of which usually not even one is properly understood.

Another common fault among students

Students try to master too many different fields at once. If they study six hours a day, they often divide that time among six separate subjects. Clearly, this fault arises from the same cause as those mentioned above. If students who study this way truly understood that such a method is not suited to their mental capacity, and that it only fills the mind with confusion and error rather than real knowledge, they would not be carried away by their uncontrolled passions and vanity. For in truth, this approach does not satisfy their desire for distinction—it guarantees that they will end up knowing nothing at all.