При использовании 
$this->authorize('index', Post::class) возвращается страница 403, а при 
Post::find(1)->can('index', Post::class) возвращается ошибка 
Call to undefined method App\Models\Post::can()
web.php:
Route::get('/', [UserController::class, 'index']);
UserConroller.php:
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\Models\User;
use App\Models\Post;
class UserController extends Controller
{
    public function index(Request $request)
    {
        $this->authorize('index', Post::class);
    }
}
PostPolicy.php:
namespace App\Policies;
use App\Models\User;
use Illuminate\Auth\Access\HandlesAuthorization;
class PostPolicy
{
    use HandlesAuthorization;
    public function index()
    {
        return true;
    }
}
AuthServiceProvider.php:
protected $policies = [
     Post::class => PostPolicy::class,
];