How Do We Know We Know?
During the early stages of modern philosophy (as distinguished from medieval philosophy) - that is, around the seventeenth century in Europe - the question that was troubling philosophers was this: how do we know that we know?
The early modern scientists had made advances in the physical sciences by rejecting previous human authority. For example, they rejected much of what had been inherited from the science of the Middle Ages. At that time, investigation had been governed and restrained by the concepts of Aristotle. In the field of astronomy, this had meant that the Ptolemaic system held sway. Suddenly, observations were made which cast doubt on that entire system of understanding the heavenly bodies. The result was, of course, the Copernican revolution: the discovery that the sun does not move around the earth but, rather, the earth around the sun. Thus, a general attitude was developed toward the ideas which had prevailed till then. The scientists said, "We must not accept the ideas passed down to us or derived from various previous authorities. We must start from scratch and simply observe the world and see how it works. Otherwise, we may be hampered from seeing what is there."
The early modern scientists did not, however, reject the knowledge that God gave in the Bible as they rejected previous human authority and opinion. For example. in Novum Organum (1620) Francis Bacon wrote: "To conclude, therefore, let no man out of weak conceit of sobriety, or an ill applied moderation, think or maintain that a man can search too far of be too well studied in the book of God's word, or in the book of God's works."81 "The book of God's word" is the Bible. "The book of God's works" is the world which God has made.
Modern scientists in general lived, thought, and worked in the framework of rejecting human authority, while respecting what was taught in the Bible in regard to the cosmos - right up to the time of Michael Faraday and James Clerk Maxwell in the second half of the nineteenth century.
The philosophers (and later the materialistic scientists) went further. Their error was to confuse the escape from past human authority (which was indeed confining) with putting man at the center and rejecting God's authority as well. They wanted to reject all outside authority. They wanted to establish everything only on human observation. That was how the question of epistemology (how we know we know) became so important in modern philosophy. It has remained so right up to our own day.
The philosopher who first raised these questions was Rene Descartes (1596-1650). Descartes wrote in Meditations on First Philosophy:
How often it happened to me that in the night I dreamt that I found myself on this particular place ... whilst in reality I was lying on my bed! At this moment it does seem that it is with eyes awake that I am looking at this paper .... But in thinking over this I remind myself that on many occasions I have in sleep been deceived by similar illusions, and in dwelling carefully on this reflection I see so manifestly that there are no certain indications by which we may clearly distinguish wakefulness from sleep that I am lost in astonishment. And my astonishment is such that it is almost capable of persuading me that I now dream.82
Here is the modern epistemological problem expressed three centuries ago! All knowledge comes through the senses, but how can we rely on our own senses? Sometimes, as in dreaming, we seem to be experiencing things very really, yet the reality is only in our heads.
We are reminded of the 1966 film by Michelangelo Antonioni called Blow-Up, in which one of the central issues was this same question. A photographer had taken a picture of a murdered man in a park in London and then became uncertain whether this was, in fact, part of reality or an experience of fantasy similar to a drug trip. Within the humanist world-view there is no final way of telling. And Antonioni ends his film by making the point graphically. Tennis players play the game without a ball. The invisible "ball" goes back and forth and the spectators watch its "path" from side to side until finally the "ball" (which does not exist) goes out over the surrounding wire and "falls" at the photographer's feet. He pauses for a moment, uncertain about what he should do. (Is observation simply a matter of the majority? Does the reality of things come from the general agreement in society and nothing more?) Then the photographer stoops down, picks up the "ball," and throws it back onto the court. Here, depicted brilliantly, is the problem of any system which builds its epistemology on man alone. This film was a philosophic statement of the period in which we are living.
Take another example out of the history of this new approach in philosophy, that of David Hume (1711-1776). In 1732 he shocked the world with A Treatise of Human Nature. John Locke (1632-1704) had already denied the concept of "innate ideas" of right and wrong; that is, Locke denied that these ideas are inherent in the mind from birth. This had troubled many. Then Hume burst on the scene with a challenge which went further.
What was most startling was his progression beyond skepticism concerning God and other things of the "invisible world" to a skepticism about the visible world as well. Among other things, he questioned the concept of causality. That is, Hume challenged the notion that there is a reality in the external world which leads us to speak about one thing as being the cause of another. When we see a tree bending and swaying and its leaves falling to the ground and racing off across the field, we naturally speak of the wind as causing this phenomenon. Hume challenged this.
Following on from Locke, who said that all knowledge comes only from the senses, Hume argued that causality is not perceived by the senses. What we perceive are two events following closely upon each other. It was custom, he argued, which led us to speak in terms of causality, not any objective "force" working in the things themselves. Anyone can see where this thinking leads, and it was so understood at the time. If causality is not real, science becomes impossible - for what scientists are doing is tracing the path of cause and effect from one event to the next.
A modern British humanist, Kathleen Nott, has written perceptively about Hume in Objections to Humanism (1967): "Among great philosophers, Hume ... hung his nose as far as any over the nihilistic abyss."83 This is right. Hume was questioning the most basic elements of our experience. Yet he was trying to be consistent to his presuppositions (that is, his starting point). Where did this lead him? To a skepticism about knowledge itself. Hume wrote designedly against the Christian world-view which prevailed in England at the time. He wanted to dismantle the system of ideas which came out of the Bible, of a God before whom man was responsible, of people being more than matter, of a life after death which seemed to defy all natural law. Where he ended, though, was with uncertainty even about the ordinary things of life. As Kathleen Nott continues: "Hume's philosophizing was indeed a radical skepticism, which left no convincing logical grounds for believing that anything natural, let alone supernatural, was there at all."84
But there is something even more striking about Hume. Skepticism was the direction in which his philosophy led him; yet he was not able to live with it himself. He "hung his nose over the nihilistic abyss" - and we can picture him standing on the edge and peering over - but what then? Nott says he "withdrew it sharply when he saw the psychological risks involved." Hume himself said in A Treatise of Human Nature (Volume I):
Should it be asked me whether I sincerely assent to this argument which I have been to such pains to inculcate, and whether I be really one of those skeptics who hold that all is uncertain ... I ... should reply ... that neither I nor any other person was ever sincerely and constantly of that opinion ... I dine, I play backgammon, I converse and am merry with my friends; and when, after 3 or 4 hours amusement, I would return to these speculations, they appear so cold and strained and ridiculous that I cannot find in my heart to enter into them any further. Thus the skeptic still continues to reason and believe, though he asserts that he cannot defend his reason by reason; and by the same rule, he must assent to the principle concerning the existence of body, though he cannot pretend, by any argument of philosophy, to maintain its veracity.85
We believe there are only two basic alternatives in the search for the source of knowledge. One is that a person attempts to find the answers to all his questions alone. The other is that he seeks revealed truths from God. We shall come to the second later. Now we are looking at the former, and we are suggesting that this is the basic problem with which all humanistic systems must wrestle: the problem of knowledge.
We could go into many other details concerning the subsequent history of the ideas we have dealt with, including in particular Immanuel Kant (1724-1804) and his own "Copernican revolution" in philosophy and also the developments surrounding Ludwig Wittgenstein (1889-1951) and linguistic philosophy in the twentieth century. We shall stop here, partly to keep the discussion of modern philosophy from becoming too technical, but mainly because the basic difficulties had already been expressed within a century of the birth of modern philosophy.
Starting with himself, a person cannot establish an adequate explanation for the amazing possibility that he can observe the world around him and be assured that his observations have a correspondence with reality. The problem is not just that a person cannot know everything. The need is not for exhaustive knowledge; the need is for a base for any knowledge at all. That is, even though we know we cannot exhaustively perceive even the smallest things in our experience, we want assurance that we have really perceived something - that is "perception" is not simply an "image" in our brain, a model or symbol of reality which we have projected out from ourselves. We want to know that we have had a real contact with reality. Even Hume had to admit that his philosophizing did not make sense, that it did not fit into his own experience of the world. On the humanist side this is the great tension - to have no reason for reason and yet at the same time to have to live continuously on the reality of reason.
At this point, someone is bound to ask, "But why is it necessary to have an `adequate explanation' for knowledge?" Agreeing that Descartes, Hume, and others could find no theoretical base which tied in with their experience, isn't it sufficient to just reason? Probably many of you have been wanting to ask this, as you have followed along. It is a good question, for the bulk of the world never bothers about the issues which Locke, Hume, and others like them raised. Most people simply live, going about their daily lives, never troubling themselves about reality and fantasy, the subject and the object, and so on. And we are not suggesting that their experience in itself is invalid, as if to imply that they are not perceiving and knowing the universe around them. They are. What we are saying is that - whether they know it or not - their experience is possible only because they are living in the universe the Bible describes, that is, in a universe which was created by God. Their internal faculty of knowing was made by God to correspond to the world and its form which He made and which surrounds them.
If, however, we attempt to bypass the question, "Why is it possible for man to have knowledge in this way?" we must then remember the other two great problems any system which starts only from man. Recall the illustration of the oil tanker and the rock. The rock is the problem of knowledge which we have been considering. That is the central problem. But there are two forms of pollution which flow from the broken ship of knowledge: first, the meaninglessness of all things and, second, the relativity of morals.