Guest users in laravel authorization policies

I use policies for user authorization. How to use policies for guest users?

Here is my code:

In controller:

class PostController extends Controller
{
    public function index(Post $post)
    {
        $this->authorize($post);
        return $post->all();
    }
}

In policy:

class PostPolicy
{
    public function index(User $user)
    {
        // This code executes only for authenticated users.
        // I want to use it for guest users too
        return $user->can('get-posts');
    }
}

via Chebli Mohamed