This quote is an affirmation of the importance and reliability of mathematics as a discipline. It suggests that mathematics, with its logical precision and absolute certainty, is a key to understanding the world around us. In other words, without a grasp of mathematical principles, one’s understanding of the world is incomplete and muddled.

The "supreme certainty of mathematics" refers to the absolute and unchanging nature of mathematical truths. For instance, the sum of the angles in a triangle will always be 180 degrees, no matter what. This certainty, this absolute truth, is what sets mathematics apart from other disciplines. It’s a language that describes the universe in its most fundamental form.

Applying this to today’s world, the quote underscores the importance of numerical literacy in navigating modern life. From understanding statistics in a news report to making financial decisions, a basic understanding of mathematics is crucial. It is also a fundamental tool in various fields such as engineering, physics, economics, computer science, data analysis, and more. In these fields, the unchanging truths of mathematics provide a solid foundation upon which complex theories and technologies are built.

On a personal development level, understanding mathematics can enhance problem-solving skills, logical thinking, and decision-making abilities. It encourages us to think critically and analytically, to question and probe until we find solutions. This is a valuable skill not just in mathematical problems, but in life’s challenges as well.

In conclusion, the quote emphasizes that understanding mathematics is not just about numbers and equations, but about achieving clarity in thought and action. Without it, we risk misunderstanding the world around us and making misguided decisions.