You will find slackers at Ivies and intellectuals at community colleges as well. You will also find intellectual conversations for fun and stupid discourses both inside penitentiaries and churches. Having gotten that out of the way, the question the OP is most likely trying to figure out is where intellectual debate is pervasive i.e. a LARGER proportion of the student body and, for that matter, faculty engage in philosophical conversations for fun and not for grades or looking cool or to one day stand for President. It is an oversimplification to mention that you can get intellectuals everywhere and that college is what you make of it. Thats a non-answer answer and every kid knows that.
If a college has an overwhelming number of jocks or purely academic nerds or selfie-taking partiers, chances are the OP will have a harder time freely discussing whether declaring prostitution illegal is an infringement of individual rights or similar issues or whether Plato’s Republic is an increasingly flawed text - even if they did not take a class in philosophy. Also bear in mind that jocks typically do poke fun at such debate so being surrounded by them will not be conducive to having philosophical discussions.
Colleges that have a mix of all kinds of people (typically the huge UCs, UF, UMich etc but probably not BYU) do not have any particular philosophically polarizing identity and you typically get an opportunity to interact with multiple types of people. There is, however, an identity that defines literally every small LAC - from the conservative CMC to the ultra-liberal Reed. How many know that Swarthmore for example took a stand against McCarthyism and hosted the Head of the UC Communist Party for a lecture in the 50s during the height of the witch hunts? Or that Steve Jobs had applied only to Reed College because of what it stood for and he refused to go to any other college?
There are absolutely colleges that attract one type of kids be it the philosophers, the jocks, the academics, the cruise-on-papa’s-dimers, the partiers or the deep thinkers. Kids also like to be with other who are they can relate to more easily. There are certain schools our kids will fit better into culturally. That needs to be kept in mind. Your reserved deep thinker’s decision to attend a boisterous sports focused university (for example Alabama) might open him or her up to other things or make them miserable.
** Too much time today waiting for superbowl **