by Joseph Shieber
Credit: Wellcome Library, London.
Famously, the philosopher and mathematician Alfred North Whitehead referred to all of philosophy as “footnotes to Plato.” Actually, he wrote that, “The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato. I do not mean the systematic scheme of thought which scholars have doubtfully extracted from his writings. I allude to the wealth of general ideas scattered through them.” (Whitehead, Process and Reality)
Now, Whitehead intended this statement as a tribute to “the wealth of general ideas” that we can find in Plato. There is, however, another way to read the statement, a way that is not flattering at all to philosophy itself.
According to this other, less flattering reading, all of the major ideas that are still discussed by philosophers were already there in Plato, thousands of years ago. There are at least two ways in which this reading is unflattering for philosophy.
First, and most obviously, the statement suggests that there have been no significant new ideas in philosophy for over 2000 years. The big ideas, so the statement would have it, were already there in Plato; all the philosophers since Plato have only been able to add contributions worthy of nothing more than footnotes – that is, commentary or minor improvements.
Second, the statement paints an unflattering picture even when you consider the – plausible – point that not all philosophers after Plato have agreed with his positions. Here are a few reasons why.
One of the strengths of Plato is that he often considered not only interesting philosophical questions, but also different answers to those questions. So, for example, when Plato considers the question, “What is Knowledge?”, in the Theaetetus, he weighs different answers to that question.
Suppose, for the sake of argument, that Plato presents five different views on the nature of knowledge, rejects four of those views, and endorses one. In that case, Whitehead would – at least in some sense – still be justified in saying that a philosopher who endorses any of the five views – even one of the views rejected by Socrates – would be offering commentary to Plato. This is because Plato has already mapped the space of possible positions; all subsequent philosophers, to this way of thinking, are simply arguing about where we’re situated in that space – which of the possible positions is the actual position we ought to stake out for philosophy.
There is an additional reason, on this second reading, for skepticism about progress in philosophy. That’s because even those philosophers who disagree with Plato cannot contribute to progress in philosophy, unless there is some way to settle that disagreement. But there is no way to settle that disagreement – if by “settling the disagreement” what we mean is that there are no longer any proponents of the “losing” position.
The great 20th century philosopher of science Thomas Kuhn puts the point this way:
If we doubt, as many do, that non-scientific fields make progress, that cannot be because individual schools make none. Rather, it must be because there are always competing schools, each of which constantly questions the very foundations of the others. The man who argues that philosophy, for example, has made no progress emphasizes that there are still Aristotelians, not that Aristotelianism has failed to progress. (Kuhn, The Structure of Scientific Revolutions)
In biology, you no longer find any prominent defenders of Lysenkoism or Lamarckism. There are no proponents of the Ptolemaic system in astronomy, or of Aristotelian mechanics in physics. In contrast, as Kuhn’s quote suggests, the fact that – after more than 2000 years – we still have proponents of ever more sophisticated and subtle versions of Platonism, Aristotelianism, Thomism, Humeanism, or Kantianism, just to name a few prominent examples, would seem not to reflect well on the idea of progress in philosophy. (For a detailed argument suggesting that the entire history of philosophy involves the recurring rise and fall, and rise again, of only a few – less than ten! – different basic philosophical positions, see Randall Collins, The Sociology of Philosophy.)
Perhaps, however, the comparison between philosophy and the natural sciences is inapt. Consider, instead, the case of mathematics. Famously, there are consistent systems of geometry that are independent of each other, depending on whether – and, if so, how – those systems involve the rejection of Euclid’s parallel postulate. Analogously, there are consistent axiomatic systems for set theory that are independent of each other, depending on the status of Cantor’s Continuum Hypothesis in those systems. With this comparison in mind, you could see competing schools of philosophy as independent, internally consistent systems of thought.
There are internal questions, such as whether Aristotle’s system allows for the possibility of genuine akrasia or whether Kant can make sense of the thing-in-itself, and then there are external questions, such as whether we ought to adopt a Thomistic or a Humean notion of causation.