ABSTRACT
It is sometimes said that a sentence expresses a complete thought. This is a notional definition: it defines a term by the notion or idea it conveys. The difficulty with this definition lies in fixing what is meant by a ‘complete thought’. There are notices, for example, that seem to be complete in themselves but are not generally regarded as sentences: Exit, Danger, 50 mph speed limit. On the other hand, there are sentences that clearly consist of more than one thought. Here is one relatively simple example:
This week marks the 300th anniversary of the publication of Sir Isaac Newton’s Philosophiae Naturalis Principia Mathematica, a fundamental work for the whole of modern science and a key influence on the philosophy of the European Enlightenment.
