interrupt/counter

I guess I'm a special needs kind of person. I apologize, interrupts are new to me.

this is what i have now

ERROR CODE

Arduino: 1.8.5 (Windows 10), TD: 1.41, Board: "Teensy 3.2 / 3.1, Serial, 72 MHz, Faster, US English"

SIX:65: error: 'void Dim()' redeclared as different kind of symbol
 void Dim () {

          ^

G:\arduino\SIX\SIX.ino:8:15: note: previous declaration 'volatile byte Dim'

 volatile byte Dim;               // interupt name

               ^

SIX: In function 'void setup()':
SIX:33: error: invalid conversion from 'byte {aka unsigned char}' to 'void (*)()' [-fpermissive]
   attachInterrupt(digitalPinToInterrupt(dimmerSwitchISR), Dim, FALLING);

                                                                       ^

In file included from F:\Arduino\hardware\teensy\avr\cores\teensy3/wiring.h:38:0,

                 from F:\Arduino\hardware\teensy\avr\cores\teensy3/WProgram.h:45,

                 from F:\Arduino\hardware\teensy\avr\cores\teensy3/Arduino.h:3,

                 from C:\Users\Landon\AppData\Local\Temp\arduino_build_402341\sketch\SIX.ino.cpp:1:

F:\Arduino\hardware\teensy\avr\cores\teensy3/core_pins.h:1931:6: note:   initializing argument 2 of 'void attachInterrupt(uint8_t, void (*)(), int)'

 void attachInterrupt(uint8_t pin, void (*function)(void), int mode);

      ^

SIX: In function 'void Dim()':
SIX:65: error: 'void Dim()' redeclared as different kind of symbol
 void Dim () {

           ^

G:\arduino\SIX\SIX.ino:8:15: note: previous declaration 'volatile byte Dim'

 volatile byte Dim;               // interupt name

               ^

'void Dim()' redeclared as different kind of symbol

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PROGRAM CODE

volatile byte dimmerSwitchISR = 9;    // temporary switch for counter. counter is pwm for led dimmer
byte dimmerCount;               // track button press
int dimmerValue;                // set PWM with counter 0-3
volatile byte Dim;               // interupt name
byte ledRred = 3;               // red LED right side
byte ledRyellow = 4;            // yellow LED right side
byte ledLyellow = 5;            // yellow LED left side
byte ledLred = 6;               // red LED left side
const byte irA = 21;            // middle sensor, address selection
const byte irB = 22;            // right side sensor, address selection
const byte irC = 23;            // left side sensor, address selection
int battSensor = A0;            // read battery voltage, pin 14 on teensy
int hotPixleValue;              // amount of pixles from sensor that are detecting heat


void setup() {
  // put your setup code here, to run once:

  // pinMode(dimmerSwitchISR,INPUT_PULLUP);
  pinMode(ledRred, OUTPUT);
  pinMode(ledRyellow, OUTPUT);
  pinMode(ledLyellow, OUTPUT);
  pinMode(ledLred, OUTPUT);
  pinMode(irA, OUTPUT);
  pinMode(irB, OUTPUT);
  pinMode(irC, OUTPUT);
  dimmerCount = 1;

  attachInterrupt(digitalPinToInterrupt(dimmerSwitchISR), Dim, FALLING);
}

void loop() {
  // put your main code here, to run repeatedly:


  /*if (digitalRead(dimmerSwitch) == LOW){
      //dimmerCount++;
    }*/
  if (dimmerCount == 3) {
    dimmerCount = 0;
  }
  if (dimmerCount == 0) {
    dimmerValue = 40;
  }
  if (dimmerCount == 1) {
    dimmerValue = 115;
  }
  if (dimmerCount == 2) {
    dimmerValue = 255;
  }

  analogWrite(ledLyellow, dimmerValue);
  analogWrite(ledLred, dimmerValue);
  analogWrite(ledRred, dimmerValue);
  analogWrite(ledRyellow, dimmerValue);
  delay(160);


}

void Dim () {
  dimmerCount++;
}