It's my opinion. Primary consciousness came first in evolution, and is necessary for higher-order consciousness, according to the TNGS. Vertebrates and many other animals have primary consciousness. It took hundreds of millions of years for primary consciousness to evolve, while fully developed higher-order consciousness in humans marked by the full fruition of language abilities is a relatively recent evolutionary development, certainly within the last million years or less. Building a machine with primary consciousness will be hard enough, if even possible.