Laudator Temporis Acti

Leonardo Bruni (1370-1444), De Studiis et Litteris Liber ad Baptistam de Malatestis 5 (tr. Craig W. Kallendorf):

The most important rule of study is to see to it that we study only those works that are written by the best and most approved authors, and avoid the crude and ignorant writings which only ruin and degrade our natural abilities. The reading of clumsy and corrupt writers imbues the reader with their own vices and infests his mind with a similar corruption. Study is, so to speak, the pabulum of the mind by which the intellect is trained and nourished. For this reason, just as gastronomes are careful in the choice of what they put in their stomachs, so those who wish to preserve purity of taste will only allow certain readings to enter their minds.

Caput vero huius diligentiae ruerit videre primum, ut in eorum tantum librorum, qui ab optimis probatissimisque latinae linguae auctoribus scripti sunt, lectione versemur, ab imperite vero ineleganterque scriptis ita caveamus, quasi a calamitate quadam et labe ingenii nostri. Inquinate enim inepteque scriptorum lectio vitia sua lectori affigit et mentem simili coinquinat tabe. Est enim veluti pabulum animi, quo mens imbuitur atque nutritur. Quam ob rem, ut ii, qui stomachi curam habent, non quemvis cibum illi infundunt, ita, qui sinceritatem animi conservare volet, non quamvis lectionem illi permittet.