How do I write an essay about the significance of Fahrenheit 451 using "he is no wise man that will quit a certainty for an uncertainty?"

Beatty quotes this line (from Samuel Johnson, a famous English writer of letters) when they are in the firehouse. This is shortly before they go to Montag's house. This is Beatty's way of trying to confuse Montag. He is using literary insights in order to challenge other literary insights. Beatty is trying to prove that all of this deep thinking simply leads to impasse after impasse. One could easily find another Johnson quote that could...

Beatty quotes this line (from Samuel Johnson, a famous English writer of letters) when they are in the firehouse. This is shortly before they go to Montag's house. This is Beatty's way of trying to confuse Montag. He is using literary insights in order to challenge other literary insights. Beatty is trying to prove that all of this deep thinking simply leads to impasse after impasse. One could easily find another Johnson quote that could be interpreted to embrace uncertainty. ("The joy of life is variety." This is taken from the same work that Beatty quotes, The Idler.) 

The larger irony is that Beatty uses a quote that is easily disproved in Montag's case. He (Montag) would be wise to quit the certainty of his life (as a book-burning fireman and passive, thoughtless citizen) for a new way of life. Curiosity began his new life and as he gains more insights and knowledge, it is his wisdom that suggests an uncertain future is preferable to the old life that he (Montag) has now come to despise. This is a starting point for an essay. Uncertainty, in the context of Montag's transformation, is something he is actively seeking. In his old life, he was satisfied with the comfort of certainty. Learning new things and being open to new ideas requires one to embrace some amount of uncertainty. 

Anyone can find literary quotes that contradict each other. That's all Beatty is doing here. So, clearly this does not mean that literature and philosophy are necessarily pointless. Montag must go beyond this kind of superficial scholarship. Coming from a society in which he was a passive man and moving into a life of curiosity and deeper thinking is new territory for Montag. It therefore requires him to go to uncertain places. In other words, he actually must quit the certainty of his old life in order to pursue wisdom.