Institutio Oratoria

And in truth that god, who was in the beginning, the father of all things and the architect of the universe, distinguished man from all other living creatures that are subject to death, by nothing more than this, that he gave him the gift of speech.

For as regards physical bulk, strength, robustness, endurance or speed, man is surpassed in certain cases by dumb beasts, who also are far more independent of external assistance. They know by instinct without need of any teacher how to move rapidly, to feed themselves and swim.

Many too have their bodies clothed against cold, possess natural weapons and have not to search for their food, whereas in all these respects man's life is full of toil. Reason then was the greatest gift of the Almighty, who willed that we should share its possession with the immortal gods.

But reason by itself would help us but little and would be far less evident in us, had we not the power to express our thoughts in speech; for it is the lack of this power rather than thought

The construction of a soft lair, the weaving of nests, the hatching and rearing of their young, and even the storing up of food for the coming winter, together with certain other achievements which we cannot imitate, such as the making of honey and wax, all these perhaps indicate the possession of a certain degree of reason; but since the creatures that do these things lack the gift of speech they are called dumb and unreasoning beasts.