The Hypothetical "You" in Russian

In this post I want to talk about an an area of Russian grammar and stylistics that doesn't get mentioned too often.  This post will deal with the hypothetical "you" in Russian.  The hypothetical "you" is what one would use in a context when referring to a hypothetical, undefined person.  In English, the hypothetical "you" is included as one of the meanings of the pronoun you when in an informal context, but in more formal contexts it is generally expressed with the word one.  (Example:  One must be careful when crossing the street.)  As seen in the example sentence, this kind of construction is common with aphorisms, popular sayings, warnings, and other contexts where the speaker wants to make a generalization, but does not want to directly refer to any particular person, including the person or persons with whom he is having a conversation.

Expressing this in Russian is different than in English.  You have to use an односоставное предложение (in this context, it means a sentence where the subject pronoun is omitted) that uses a verb with an informal 2nd person singular ending (such as -шь for the present tense, and -и/-ь for the imperative).  The pronoun ты must be omitted!  

D. E. Rosenthal's Russian reference gives some examples of how this construction can be used (the bold emphasis is mine, showing the two example sentences):

Любишь кататься – люби и саночки возить (односоставное в составе сложного) – Каждый, кто любит кататься, должен любить и саночки возить (двусоставное в составе сложного) первое придает высказыванию афористичность, второе – назидательность;

Both of the example sentences are grammatically correct; the difference is just in stylistics.  As Rosenthal mentions, the first sentence, using the informal endings -шь and -и, has a quality like that of a proverb.  The second sentence, which uses the infinitive, has a more "instructive" quality. 

Here is another example from Rosenthal:

Синонимия возможна также между разновидностями односоставных предложений, в частности между инфинитивными и обобщенно-личными. Ср., например, строки Тютчева Умом Россию не понять, Аршином общим не измерить; У ней особенная стать – В Россию можно только верить и потенциально возможный вариант Умом Россию не поймешь, Аршином общим не измеришь...; инфинитивные предложения отличаются большей категоричностью высказывания.

As noted by Rosenthal, the original line by Тютчев (the first bolded sentence in the quoted text) uses infinitives and has a more explicit, strict quality to it, stating that without exception, it is impossible for one to understand Russia with your mind, and that no standard unit of measurement can be used to measure Russia.  The second bolded sentence is an edited version of Тютчев's line where the two infinitives are each replaced with informal -шь endings, making the sentence sound more like a proverb or wise saying than an absolute statement of fact. 

What's interesting about all this is that it's acceptable to use the informal verb forms to express the informal "you", even when you are in a formal conversation with someone and are using the formal Вы forms.  In this case, using the informal verb forms is not considered to be breaking formality and making the conversation enter the level of familiarity; the person with whom you are talking to will know from the context that what you are saying involves the hypothetical "you" and does not apply directly to the conversation partner.  This is why the ты personal pronoun must be omitted - otherwise, what you are saying might be mistaken for familiarity.