"He is so weird" is a observational transformation that is perpetrated in variations all the time. The author transforms a subjective observation into a objective attribute, but neglects to make the transformation explicit and fails to argue its validity.
The problems with observational transformations are:
- A defining and misrepresenting attribute: Out of the infinite number of attributes that belong to a single person, only one (or a few) gets to represent all the others, which probably doesn't do the rest justice and hence acts as a misrepresentation instead of a definition.
- A closed case once performed: With the defining attribute(s) identified, it's quickly deemed irrelevant to investigate further, which places everything but the most apparent attributes at a grave disadvantage. Subtlety loses.
- A viral nature: Defining attributes are so attractive that they don't need to be delivered with much persuasion to spread quickly. Once spread, the link to the original author is lost and along with it access to the implicit arguments that formed basis for the transformation.
Learning to avoid and discourage observational transformations rests on the ability to distinguish between behavioral, appearance, and inherent attributes. The former two exists only as an interpretation and are hence bound to subjectivity, which makes them questionable candidates for defining attributes. The latter, exemplified as "this man has red hair" or "she is 18 years old", belong in the realm of objectivity, and thus makes valid candidates.
I recommend that you try evaluating your observational transformations with the distinction above in mind before uttering said transformations. Hopefully, you'll be able to see when the transformations are lacking in support, avoid lush inductive generalizations, and appear less brass to your fellow man.
I think your observation is flawed. Furthermore it seems to me that you fail to distinguish what kind of attribute you wish to discuss.
I) Predicates that implicitly refer to taste.
If I say: "This cucumber tastes absolutely awful" - it is implicit that I am making a distinct subjective statement and nothing more. I am not (presupposing a normal communicative interaction) expected to remark that this statement is purely my opinion. The statement is not, at least not in the ordinary use of language, an attempt to objectify a specific evaluation, nor the implication that other persons should feel the same way.
Either you disregard this fact, or else you seem to confuse this statement, with an assertion of fact. Third option of course and very likely, you simply feel that a statement like “he is such a nerd” needs to be justified in the same manner as any other descriptive account, say eg. “the car is red”. Hence,
II) Descriptive sentences.
The list of philosophical problems with the meaning of words and sentences is a very long one. I will try briefly to describe, what in my opinion is the main problem with your account.
Consider the following statement: “Peter is a footballer”. In this instance we are not discussing a feature of taste, but instead a certain attribute of being something, you might say an attribute of fact. Now, how are we supposed to distinguish who should be considered a footballer. In other words, what are the necessary and sufficient conditions for being a footballer. This is in fact the question you are asking in regards to being a nerd.
Now, there are more than a thousand words perhaps even ten or hundred thousands, for which it would be impossible to give an objective and even close to sufficient definition – the word footballer is just one of them. And still, you would be very bold to claim, that using these words would be a so called “Observational transformation”. In that case, a very large part of every human’s vocabulary is subjective accounts turned into observational transformations when uttered. This is not the case.
The problem is unfortunately much more complicated, and if you wish to pursue the problem, I would suggest that you read about Wittgenstein’s problem of familiarity. Or more generally try reading som introductions to the philosophy of language.
If all you were really trying to say was: “be careful before you pass judgement”, I apologise for the inconvenience. ;)