Critical spirit and tolerance are notions which do not exclude each other. As freedom without rules is not actually authentic freedom, but libertin ism (leading to chaos or barbarism), so tolerance without critical thinking (or critical spirit) leads to similar regrettable results. One can also judge the other way round, starting with critical spirit and stating that sometimes, in certain circumstances, critical spirit should be doubled by tolerance. This is what I intend to prove in my article, dealing with statements belonging to Voltaire and to Coseriu.