First we must define the terms ‘noun’ and ‘verb’, then the terms ‘denial’ and ‘affirmation’, then ‘proposition’ and ‘sentence.’ Spoken words are the symbols of mental experience and written words are the symbols of spoken words. Just as all men have not the same writing, so all men have not the same speech sounds, but the mental experiences, which these directly symbolize, are the same for all, as also are those things of which our experiences are the images. This matter has, however, been discussed in my treatise about the soul, for it belongs to an investigation distinct from that which lies before us. As there are in the mind thoughts which do not involve truth or falsity, and also those which must be either true or false, so it is in speech. For truth and falsity imply combination and separation. Nouns and verbs, provided nothing is added, are like thoughts without combination or separation; ‘man’ and ‘white’, as isolated terms, are not yet either true or false. In proof of this, consider the word ‘goat-stag.’ It has significance, but there is no truth or falsity about it, unless ‘is’ or ‘is not’ is added, either in the present or in some other tense.
Author
384 BC–322 BC Greek philosopher Aristotle, a pupil of Plato and the tutor of Alexander the Great, authored works on ethics, natural sciences, politics, and poetics that profoundly influenced western thought; empirical observation precedes theory, and the syllogism bases logic, the essential method of rational inquiry in his system, which led him to see and to criticize metaphysical excesses. German religious philosopher Saint Albertus Magnus later sought to apply his methods to current scientific questions. Philosophy of Saint Thomas Aquinas, the most influential thinker of the medieval period, combined doctrine of Aristotle within a context of Christianity. Aristotle numbers among the greatest of all time. Almost peerless, he shaped centuries from late antiquity through the Renaissance, and people even today continue to study him with keen, non-antiquarian interest. This prodigious researcher and writer left a great body, perhaps numbering as many as two hundred treatises, from which 31 survive. His extant writings span a wide range of disciplines from mind through aesthetics and rhetoric and into such primary fields as biology; he excelled at detailed plant and animal taxonomy. In all these topics, he provided illumination, met with resistance, sparked debate, and generally stimulated the sustained interest of an abiding readership. Wide range and its remoteness in time defies easy encapsulation. The long history of interpretation and appropriation of texts and themes, spanning over two millennia within a variety of religious and secular traditions, rendered controversial even basic points of interpretation.
