“Scientific and philosophic truth have parted company.”
—Hannah Arendt, The Human Condition, 41.290
What can it mean that there are two different types of truth—scientific and philosophic? And how could they not be connected?
To help us understand those two questions, Arendt describes how Galileo’s invention of the telescope transformed the traditional understanding of truth. Galileo's invention of the telescope altered the way Descartes examined the nature of being, that is, what makes a thing exist and determines the content of its existence. For Descartes, the telescope provided proof that people cannot trust either their minds or their unaided senses to give them a reliable understanding of the world. For thousands of years, people had taken what they saw in the heavens and had then used their minds to try to make sense of it. But the telescope proved them wrong. Reality was not what it appeared to be. As Arendt writes: “If Being and Appearance part company forever. . . then there is nothing left to be taken upon faith; everything must be doubted.”
The key consequence of this revelation was a loss of beauty, of what the Greeks called to kalon. Unlike the English word beautiful, to kalon describes not only physical beauty but also general suitability for a purpose or moral approval. It is therefore applicable when commending a soldier who sacrificed himself to save his companions: “That was a beautiful thing he did.”
Arendt describes the new way of approaching knowledge, for which Descartes was a catalyst, as the “un-Platonic subjection of geometry to algebraic treatment.” This changed the way we explore the knowledge of our world; people began to “reckon with entities which could not be ‘seen’ by the eye of the mind,” which in turn brought about a “novel mode of meeting and approaching nature in the experiment.” This new scientific means of understanding ultimately robbed the world of much of its beauty, for with this transformation of thought, understanding became a matter of computing rather than “a demonstration of an inherent and inherently beautiful order of nature.”
Since Descartes had evidence that human senses could not be relied on to develop an accurate picture of the world, he began to doubt and question nearly everything—even his own existence. Everything he previously thought of as real dissolved under his questioning, insofar as the only thing he came to sure of was the immeasurable doubt he felt for the world. “The famous cogito ergo sum (‘I think, hence I am’) did not spring for Descartes from any self-certainty of thought as such—in which case, indeed, thought would have acquired a new dignity and significance for man—but was a mere generalization of dubito ergo sum.”
He had nothing from which he could take his bearings. He saw the being of the things he had previously believed in as all up for correction by devices or instruments that were allegedly more reliable, more precise than people's senses and minds. This new fragile world made him recoil: without solidity, without certainty, everything was ugly. He compared ancient moral writings to “proud and magnificent palaces built only on sand and mud” and described virtues as “nothing but a case of callousness, or vanity, or desperation, or parricide.”
Philosophers since Socrates had enjoyed seeing beyond the everyday appearance of things and understanding the world on a deeper level. For them even the immaterial could be thought of through images and seen with the mind's eye. Philosophic truth had constituted success at seeing what makes a thing what it is; that sight had evoked a sense of wonder (thaumazein). For the philosopher, being was beautiful (kalos) to behold.
But Descartes—revolted by the ugliness of being, or lack of being, that became apparent from the vantage point of his analysis—sought to push back doubt, to find or to create solid ground, that is, certainty or certain truths. This is scientific truth. Truth came to be something no longer good for its own sake but something valued because it could push back the doubt, the ugliness of an uncertain world. Truth went from being an end in itself to being a means only--a means to avoid doubt. This was a fundamental shift in Western thought, and in its wake, what used to be called natural philosophy, or love of the wisdom of nature, became science.
As the human understanding of truth changed, there was a corresponding reversal from the vita contemplativa to the vita activa. The life of the mind was no longer a life searching for beauty, but in its attempts to reach the mirage of absolute certainty, it had become an interminable attempt to escape from the black-hole singularity of doubt. To continue to push back doubt, people felt compelled to make new tools and perform new experiments, all for the possibility of demonstrating that something must be true since it could be demonstrated. In this vein of thought, people could push back uncertainty via the repetition of doing, which constituted a shift “from reality to reliability.”
The result, Arendt writes, was that in “modern philosophy and thought, doubt [now] occupies much the same central position as that occupied for all the centuries before by the Greek thaumazein, the wonder at everything that is as it is.” Results had displaced beauty (to kalon), becoming the modern standard of goodness.