Some Original Sources for Modern Tales of Thales - Introduction

There are many recent history of mathematics books written for general audiences that provide information about the ancient Greek mathematician, astronomer, and philosopher Thales of Miletus.  While these general resources tend to repeat the same anecdotes and the same brief list of mathematical accomplishments, they do not always include citations of the ancient sources from which these stories are being drawn.  In some cases these books even include quotations which are ascribed to Thales, which is odd, since these modern sources will also often mention that no works written by Thales exist – and, in fact, it is openly debated whether he wrote any at all. 

The truth is, as for many figures of the distant past, the information we have about Thales is being drawn from a wide range of ancient sources, some of which contain only terse references and almost all of which were written centuries or even millennia after the time in which Thales lived.  Although these sources differ significantly in terms of content and sometimes contradict one another, there seems to be general agreement on at least the following:

• Thales lived sometime in the 6^th century BCE.
• He lived in the Greek city-state Miletus (located on the Mediterranean coast of what is present-day Turkey).
• He had a reputation in the Greek world for accomplishments in philosophy, politics, engineering, astronomy and geometry.

In this article, we will examine some of the achievements commonly attributed to Thales, and in each case explore the oldest existing historical sources that form their basis.