grammaticality - Analysis of "There is something it is like to be us"

This construction is grammatical, but awkward.

there is something [that] it is like to be us

In other words, [to be us] is like [something], as opposed to to be us is like nothing (= being us is meaningless). The relative clause [that] it is like to be us has as its antecedent something. The use of like is the same as in please tell me what it is like to be a bat.

Another way to rephrase this while keeping the relative clause is: there is something that "to be us" is like. Both in this form and in the original, that is governed by the adjective-preposition like.

Note that dummy/appositive it is often used to replace an infinitive phrase (an infinitive with arguments) when the infinitive phrase is the subject: this is what it means to be conscious. In relative clauses, this it is even more common, as even simple infinitives are somehow felt to be awkward when they would precede the finite verb; we wouldn't write *this is what to be conscious means. We would either use dummy it, or replace the infinitive with a gerund: this is what being conscious means.

In philosophy of mind, this phrase has unfortunately become popular. A different phrase would have been more transparent and easier to parse, such as:

being "us" is not a meaningless statement

Or:

The subjective aspect of existence is not the same as the objective aspect of it