Quote Originally Posted by Боб Уайтман View Post
...вишня (cherries)
черешня (cherries) - someone else has to explain the difference between вишня and черешня, can anyone help? The dictionary says вишня is Prunus cerasus and черешня is Prunus avium
Prunus cerasus sour fruit, for cooking, is pie cherry. Prunus avium is sweet cherry, for eating fresh right of tree.

Logic itself might be mass noun логик, (unless different types of logic are the topic? разные логики?).