Rowe also uses the concept of Sedimented Principles, which he attributes to the French philosopher Maurice Merleau-Ponty, one of the key figures of phenomenology. As far as I can make out, Merleau-Ponty never used the exact term "sedimented principles", but he does talk a great deal about "sedimentation".
In phenomenology, the word "sedimentation" generally refers to cultural habitations that settle out of awareness into prereflective practices. Something like the "unconscious". (Professor James Morley, personal communication)
"On the basis of past experience, I have learned that doorknobs are to be turned. This ‘knowledge’ has sedimentated into my habitual body. While learning to play the piano, or to dance, I am intensely focused on what I am doing, and subsequently, this ability to play or to dance sedimentates into an habitual disposition." (Stanford Encyclopedia of Philosophy: Merleau-Ponty)
This relates to some notions of tacit knowledge, which is attributed to Michael Polyani. There are two models that are used in the knowledge management world that talk about tacit/explicit knowledge, and present two slightly different notions of internalization.
Some critics (notably Wilson) regard the SECI model as flawed, because Nonaka has confused Polyani's notion of tacit knowledge with the much weaker concept of implicit knowledge. There are some deep notions of "unconscious" here, which may produce conceptual traps for the unwary.
Conceptual quibbles aside, there are several important points here. Firstly, enabling prejudices may start as consciously learned patterns, but can gradually become internalized, and perhaps not just implicit and habitual but tacit and unconscious. (The key difference here is how easily the practitioner can explain and articulate the reasoning behind some design decision.)
Secondly, to extent that these learned patterns are regarded as "best practices", it may be necessary to bring them back into full consciousness (whatever that means) so they can be replaced by "next practices".
Bryan Lawson, How Designers Think (1980, 4th edition 2005)
Peter Rowe, Design Thinking (MIT Press 1987)
Wilson, T.D. (2002) "The nonsense of 'knowledge management'" Information Research, 8(1), paper no. 144
Thanks to my friend Professor James Morley for help with Merleau-Ponty and sedimentation.