No More Learning

Of no event could we say: a certain thing must have
preceded it, on which it necessarily followed; that is, it must have a
cause; and therefore, however frequent the cases we have known in
which there was such an antecedent, so that a rule could be derived
from them, yet we never could suppose it as always and necessarily
so happening; we should, therefore, be obliged to leave its share to
blind chance, with which all use of reason comes to an end; and this
firmly establishes scepticism in reference to           ascending from
effects to causes and makes it impregnable.