pluralist - industrial conflict is inevitable, take it as a cost and benefit to the business and deal appropriately
radical - management are out to purposely exploit employees, industrial conflict is a way to 'get back' at them.
Just a quick distinction between the two ..
edit: Just incase my definition of Radical looked a little .. well .. 'radical'
, the textbook also highlights it as being an 'inbalance of power' between employers and employees, in which the employees feel they have to 'overthrow' their masters.