Frege, Gottlob

"Every statement is either true or false."

"The senses deceive us, but logic does not."

"We must examine our thoughts critically."

"Objects exist independently of our thoughts about them."

"Clarity in thought requires precision in language."

"Numbers are not empirical objects."

"A proposition is either true in all respects or false."

"Thinking is not a private mental act."

"We must distinguish appearance from reality."

"Logic is prior to all other sciences."

"The law of excluded middle is inviolable."

"Meaning cannot be reduced to psychology."

"We discover truths; we do not create them."

"Consistency is the hallmark of sound reasoning."

"Mathematics is about abstract objects."

"Every thought has a determinate sense."

"Truth is objective and mind-independent."

"Language mirrors the structure of thought."

"We must seek necessary, not merely probable, truths."

"The foundations of arithmetic are purely logical."

"Concepts stand in fixed relations to one another."

"Thinking requires discipline and rigor."

"A true thought corresponds to reality."

"We are servants of truth, not masters of it."

"The meaning of a word must be specified clearly."

"Nothing can both be and not be simultaneously."

"Logical laws are laws of being, not merely of thinking."

"Numbers are not properties of external things."

"Every concept divides objects into classes."

"Truth stands above all human concerns."