diff --git a/fluid/eventManager.lua b/fluid/eventManager.lua
index 0283a27..2362572 100644
--- a/fluid/eventManager.lua
+++ b/fluid/eventManager.lua
@@ -22,7 +22,9 @@ function EventManager:emit(name, ...)
    return self
 end
 
-function EventManager:register(name, listener, callback)
+function EventManager:register(name, listener, callback, enabled)
+   enabled = enabled == nil and true
+
    local listeners = self.listeners[name]
 
    if not listeners then
diff --git a/fluid/instance.lua b/fluid/instance.lua
index 720a3ec..00fbce7 100644
--- a/fluid/instance.lua
+++ b/fluid/instance.lua
@@ -9,9 +9,7 @@ Instance.__index = Instance
 function Instance.new()
    local instance = setmetatable({
       entities     = List(),
-      systems      = List(),
-      systemCount  = {},
-      eventManager = EventManager(),
+      systems      = {},
    }, Instance)
 
    return instance
@@ -38,23 +36,26 @@ function Instance:removeEntity(e)
    end
 end
 
-function Instance:addSystem(system, eventName, callback)
-   self.systemCount[system] = (self.systemCount[system] or 0) + 1
-   self.systems:add(system)
+function Instance:addSystem(system, eventName, callback, enabled)
+   self.systems[eventName] = self.systems[eventName] or {}
 
-   self.eventManager:register(eventName, system, callback)
+   local i = #self.systems[eventName] + 1
+   self.systems[eventName][i] = {
+      system    = system,
+      eventName = eventName,
+      callback  = callback or eventName,
+      enabled   = enabled == nil or true,
+   }
 
    return self
 end
 
-function Instance:removeSystem(system, callback)
-   self.systemCount[system] = self.systemCount[system] - 1
-   if self.systemCount[system] == 0 then
-      self.systemCount[system] = nil
-      self.eventManager:deregister(eventName, system, callback)
-   end
+function Instance:enableSystem(system, eventName, callback)
+
+end
+
+function Instance:disableSystem(system, eventName, callback)
 
-   return self
 end
 
 function Instance:emit(...)
diff --git a/main.lua b/main.lua
index 1150623..2ec9616 100644
--- a/main.lua
+++ b/main.lua
@@ -89,9 +89,9 @@ function RandomRemover:update(dt)
    love.window.setTitle(love.timer.getFPS())
 end
 
-Game:addSystem(RandomRemover(),     "update")
-Game:addSystem(RectangleRenderer(), "draw")
-Game:addSystem(CircleRenderer(),    "draw")
+Game:addSystem(RandomRemover(),     "update", nil, true)
+Game:addSystem(RectangleRenderer(), "draw", nil, true)
+Game:addSystem(CircleRenderer(),    "draw", nil, true)
 
 for i = 1, 100 do
    local e = Entity()