Then there's even more scattering around of the logic.

Good way:

  PhysicsEngine {
    List<Entities> entities;
    doCollisions() {
      // Logic involving instanceof
    }
  }

Bad way:

  PhysicsEngine {
    List<Entities> entities;
    doCollisions() {
      // Delegate to whomever.
      entities.forEach(e -> e.collide());
    }
  }

  Dog {
    collide() {
      // What the hell can I do here?
      // I don't know about the rest of the world
    }
  }

  Car {
    collide() {
      // What the hell can I do here?
      // I don't know about the rest of the world
    }
  }

Worse way:

  PhysicsEngine {
    List<Entities> entities;
    doCollisions() {
      // Delegate to whomever.
      entities.forEach(e -> e.collide());
    }
  }

  Dog : PhysicalObject {
    collide() {
      super.collide();
    }
  }

  Car : PhysicalObject {
    collide() {
      super.collide();
    }
  }

  PhysicalObject  {
    collide() {
      // Not only do I not know about the rest of the world
      // I don't even know how *I* collide, because what am I?
    }
  }