The phrase "an internal reason" is correct and usable in written English.
It can be used when discussing motivations or justifications that originate from within an individual or organization, rather than external factors.
Example: "The decision was based on an internal reason that was not immediately apparent to the team."
Alternatives: "a personal reason" or "an intrinsic reason".
You have to find out how to get there, to have an internal reason.
For example, "I want to write a book because it's a life-long ambition" is an internal reason.
Blaming in these cases functions as a 'proleptic mechanism': it itself changes the situation for the agent so that she now has an internal reason that she otherwise would have lacked (1989).
He can get to the motivation not to drink it by a sound deliberative route from where he already is; hence, by (b), he has an internal reason not to drink the petrol.
He says the internal reasons thesis is the view that, unless I actually have a given motive M, I cannot have an internal reason corresponding to M. The petrol/ gin case is then to be understood by cashing out the "corresponding": my motivation to drink gin readily yields a corresponding reason for me not to drink this, since this is petrol, not gin.
A positive (double negative) feedback formed by activated Bax-Bcl-2 interactions could be an internal reason of the emergence of this bio-switch.
We are not obliged to say, absurdly, that this person has a genuine internal reason to drink petrol, nor to say, in contradiction of the internal reasons thesis, that this person has a genuine external reason not to drink what is in front of him.
Perhaps there is an internal bureaucratic reason to identify interstate highways by their predominant direction over their full length, but the purpose of posting signs is supposedly to help the driver figure out which way to go.
When I questioned myself about what my personal work would be, the internal reason for making art, I couldn't even say I was a photographer.
Williams here distinguishes internal and external reasons, proposing that the truth conditions of internal reason statements be supposed essentially to involve facts about the motivations of the agent whereas those of external reasons should not.
But in cases where someone had no internal reason to do (what we take to be) the right thing that they did not do, it was not in fact true that they had any reason to do that thing; for internal reasons are the only reasons.
