Bertrand Russell was one of the most prominent logicians of the 20th century, and he had a profound impact on the development of modern logic. He was a proponent of using logic as a tool for clarifying and systematizing knowledge, and he believed that it could help to resolve many of the philosophical problems that had long puzzled thinkers.

However, in his later years, Russell became somewhat disillusioned with the limits of formal logic. He began to see it as an important but ultimately limited tool, incapable of fully capturing the richness and complexity of human thought and experience.

One of his most famous quotes on this topic is, "All definite knowledge - so I should contend - belongs to science; all dogma as to what surpasses definite knowledge belongs to theology. But between theology and science there is a no man's land, exposed to attack from both sides; this no man's land is philosophy." This quote reflects his belief that logic, while an important tool for philosophy, cannot answer all of the questions that philosophy seeks to address.

In his earlier works, such as "The Principles of Mathematics" and "Principia Mathematica," Russell held a strong view of logic as a foundation of mathematics and as a tool for the analysis of language and thought. However, in his later works, he became more critical of the limits of formal logic and its ability to capture the complexity of human thought.

Russell also wrote, in his essay "The Philosophy of Logical Atomism," he wrote, "The aim of philosophy is to make logical constructions that are sufficiently like the constructions of mathematics to serve as models for them, and to imitate the logical guarantees of science." This quote expresses Russell's belief that logic and mathematics are closely related, but also acknowledges that they are human constructions and may not necessarily correspond to objective reality.