Question: What are the import and meaning of **like** in 'to seem **like**' ? (<https://english.stackexchange.com/a/11324/50720> is mute on this.) Why is **like** necessary? 'seem' alone already means:

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> [seem](http://www.oxforddictionaries.com/definition/english/seem) [no object] = 1. Give the impression of being something or having a particular quality
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Based on <http://grammar.ccc.commnet.edu/grammar/conjunctions.htm>, I guess that **like** here is a preposition and not a conjunction? How do you determine/deduce this rigorously? 

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> Strictly speaking, the word **like** is a preposition, not a conjunction
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Obiter dictum: I focus on 'to seem like' here, compared with this question on [the differences](https://ell.stackexchange.com/q/47620/8712).

Answer: 
According to The free dictionary, contra can be used as a prefix, noun, preposition, or adverb. 

I think the contra used in the sentence is a preposition to mean in contrast to, against, or contrary to, as you understand. However, if used as a preposition, I don't think it's appropriate to put a comma before "contra". An example of its use as a preposition is mentioned in a dictionary as follows:

CONSIDER THE PROBLEMS OF THE TEENAGER CONTRA THOSE OF THE ADULT.
You are correct, it is short form for contrary to. In this instance it is being used as a preposition.