We are up to Pirkei Avos, chapter 3, mishnah 9 (in some versions it appears in the middle of mishnah 7). The words of the mishnah are said in the name of Rabbi Yaakov, and it is not even clear exactly who he was; some hold that he was the father of Rabbi Elazar ben Yaakov.
"Hamehaleich baderech v'shoneh, umafsik mimishnaso v'omer: mah na'eh ilan zeh, umah na'eh nir zeh - ma'aleh alav hakasuv k'ilu mischayev b'nafsho" - One who is walking along the road and studying, and interrupts his study and says: how beautiful is this tree, how beautiful is this field - Scripture regards him as though he bears guilt for his own life.
Explanation of the words: "Hamehaleich baderech v'shoneh" - a person who is walking along the road and learning; "umafsik mimishnaso" - he interrupts his learning and calls out: how beautiful is this tree, how beautiful is this field ("nir" - a plowed field); "k'ilu mischayev b'nafsho" - as though he is answerable for his own life, meaning that he has done something grave and terrible. This is a heavy mishnah, and it demands clarification: what is actually going on here?
The simple explanation:
The simplest way to explain this rests on a mishnah we saw earlier: a person walking along the road alone needs the protection of the Torah, and the moment he abandons it he is in danger, and the responsibility rests on him. One could say that this is the plain meaning of the mishnah, but doing so diminishes the force of the matter. It seems that this is not the mishnah's point, since it is not focused merely on the fact that he stopped learning, but on the fact that a person diverts his attention from his learning in order to be moved by the beautiful world around him.
And what is wrong with that? The answer is that in itself, being moved by the beauty of the world is not a bad thing at all. On the contrary, there is something of a mitzvah in it, and special berachos were even established to be said over the sights of creation. But all this holds true only so long as it does not come at the expense of Torah study.
Two paths to knowing the Creator:
The path of the revelation of the Torah - knowing Hashem through His Torah.
The path of creation - knowing Hashem through contemplating the works of His hands.
So the Rambam explains, and both paths are important and legitimate. Appreciating the creation of the Holy One, blessed is He, is precious (this is dealt with in the book "Signs Behind the Mishnah", and there is much to love in hiking, biking, skiing and diving, and in seeing Hashem's beautiful world). But one who wants a relationship with the Holy One, blessed is He, needs to know: the primary path is the path of Torah, and the secondary path is appreciating creation. It follows that there is a flaw in a person diverting his attention from the primary and turning to the secondary.
How beauty can drive a wedge:
In a certain sense, it is precisely out of appreciation for the beautiful world around him that a person can drive a wedge between himself and the Holy One, blessed is He. This sounds counterintuitive, since someone who looks at the world and says "wow, this is the magnificent world of the Holy One, blessed is He" seems to be connecting to his Creator - and that is not necessarily so.
Rabbi Leib Kelemen related the following about Rav Shlomo Wolbe: when he left Germany he spent some time in the yeshiva in Montreux, Switzerland, on the shore of Lake Geneva - a town as perfect as a picture postcard, a lake with mountains all around, a breathtaking sight. And he told that, to his surprise, as the days in the yeshiva went by he felt a growing distance from the Holy One, blessed is He, and he attributed that feeling of distance precisely to the splendor and beauty of the place.
What is the mechanism at work here? A person becomes so absorbed in the wondrous world that the world itself distracts him from the Creator standing behind it. It does not follow automatically that enjoying a breathtaking world will bring a person to love of Hashem. As Rabbi Kalman pointed out, a statistical study would not show that people living in stunning places like Switzerland are more religious and God fearing than those living in less scenic places like Kansas or Wyoming. That is simply not the case, because gazing at a beautiful world does not necessarily lead a person back to his Creator.
Primary and Secondary:
Connecting beauty to the Creator is a subject in its own right, and a person should make every effort to see Hashem's world and appreciate it - to the point that the Sages instituted a berachah, "shelo chisar be'olamo klum" - that He has left nothing lacking in His world, and in His world there are all good things. But one must distinguish between what is primary and what is secondary. Interrupting one's learning in order to marvel at the world pushes aside the primary matter, the central thing, and turns instead to the secondary - and that is not right.
The Story of Rabbi Zelig Epstein:
I will close with an illuminating story, part of which I saw with my own eyes. I learned for a time in Yeshiva Sha'ar HaTorah in Queens, and the Rosh Yeshiva there was Rabbi Zelig Epstein, one of the last of the Roshei Yeshiva of the old prewar world. Speaking with him was an extraordinary experience: he always looked straight ahead, because he never turned his neck, as though it were locked in place. I asked what had happened to the Rosh Yeshiva that he could not turn his neck.
In brief: when he was a boy, I believe in Grodno in the old country, a parade was held to mark the departure of the local occupying forces, and the noise carried all the way into the beis midrash. A few of the boys leaned over and peeked out the window to see what was happening, and he did so as well. At that moment he realized how easy it is to be distracted, to lean over and look. He accepted upon himself never to turn his neck again - either he is entirely inside, or entirely outside.
This is exactly how Moshe Rabbeinu conducted himself at the burning bush: "asurah na ve'er'eh" - let me turn aside and see. That is a complete and immediate response. If something is worth investigating, he gives it his full attention; and if not, he gives it no attention at all. That is total focus.
In summary: We do not mean to recommend such extreme behavior, but the point stands: a person must be focused, and while he is learning he should be in the category of "adam ki yamus be'ohel" - a man who dies in a tent, one who is dead to the world outside. The phone is off, the distractions are set aside, and he is entirely available for Torah study. And as wonderful as it is to appreciate the world around him and say "mah na'eh ilan zeh" - how beautiful is this tree, what a wondrous tree Hashem created - even that is secondary compared to the opportunity to develop a relationship with Hashem while a person learns His Torah.