Some say they are contradictory - I think that is the wrong word - complementary is more to the point.
What's the beef? Explicit
lyrics ahem... policies
One of the Kanban Principles (the fourth to be exact) requires the team to "... Make Process Policies Explicit" while the probably best known statement from the agile manifesto invites us to value "Individuals and interactions over processes and tools."
Now when Tom and I prepared our hands on lean and agile practices course we both knew from experience that there is a lot of value in both approaches. But I still was baffled when a colleague from the Limited WIP Society Cologne pointed out the contradiction in these two statements and it took me while to come up with an answer.
Explicit is not a four letter word
Many people I know in the Agile community are sceptic towards explicit rules because they tend to be written in stone – especially if they come from the outside. But in an Agile environment (same as in a lean environment) that doesn't have to be the case. Not, if the team (or the cell if you use lean terminology or however the relevant unit is called in your context) owns the process policies - whether they are explicit or implicit. Making them explicit does not make the un-changeable.
"Explicit" makes it tangible
On the contrary - as long process policies are implicit it is hard to discuss them. Once they are written down – for example as an exit condition for a status or as a work in progress limit – it is easy to refer to them (the hard part is identifying them in the first place) and the team can change them explicitly whenever the need arises. Visible to everyone and without reliance on tacit knowledge. They might even start to track how often they change certain policies as those changes might point to some opportunity for improvement and the numbers could provide valuable input for the next operations review (or retrospective if your focus is Agile)
Explicit policies make it easier...
... to focus on "Individuals and interactions over processes and tools" because the important agreements between the individuals are out there in the open – tangible and negotiable.