after.rb

class Practice < ActiveRecord::Base
  default_scope order(:name)
  
  has_many :attorneys, -> { where(active: true)}, :through => :attorney_practice_links

  has_many :attorneys_only, -> {where(active: true, is_attorney: true) },
                            :through => :attorney_practice_links, 
                            :include => [:position],
                            :source => :attorney
                            
  has_many :non_attorneys,  -> { where(active: true, is_attorney: false).order('positions.name, attorneys.last_name, attorneys.first_name') }, 
                            :through => :attorney_practice_links, 
                            :include => [:position],
                            :source => :attorney


  # ...
end

error

ArgumentError: Invalid mix of scope block and deprecated finder options on ActiveRecord association: Practice.has_many :attorneys_only

practice.rb

class Practice < ActiveRecord::Base
  default_scope order(:name)
  
  has_many :attorneys, -> { where(active: true)}, :through => :attorney_practice_links

  has_many :attorneys_only, :through => :attorney_practice_links, 
                            :include => [:position],
                            :source => :attorney, 
                            :conditions => 'attorneys.active = 1 AND positions.is_attorney = 1'

  has_many :non_attorneys,  :through => :attorney_practice_links, 
                            :include => [:position],
                            :source => :attorney, 
                            :conditions => 'attorneys.active = 1 AND positions.is_attorney = 0',
                            :order => 'positions.name, attorneys.last_name, attorneys.first_name' 

  # ...
end