Learn English – raise attention

Logically, it seems like this is the reverse of the usual process, as you explained. We would usually sooner think something than come out and say it. However, I believe in this case, he is more concerned about changing his entire philosophy by permitting such a thought to enter his mind, than about uttering words. At least that's the impression I get.

According to the Cambridge Dictionary, raise means to cause to exist. It also says that express means to show a feeling, opinion, or fact.

The difference is that raising is generally about creating something new, whereas you can express concerns about just about anything, including things that are already in the public domain.

So, I could express concerns about global warming but I could not raise them - everybody already knows about it. On the other hand I could either raise or express concerns about the possibility that a meteorite recently observed by my team might collide with the Earth - in this case I can use raise because nobody else knows about the meteorite or its path.

In your case, if somebody else has already raised these doubts, you can only use express. If you are the first group to identify them, then you can use either express or raise.