Hegel, Is There a Self Sufficient Way of Arriving at Knowledge?

We can do a double blind taste test, and our taste buds will tell us that the salt is as bitter, as opposed to sweet. But what hegel wants us to realize is that yet again, this is not a reliable means of arriving at knowledge. To even make the claim that the salt in that salt shaker is white, that implies that you had at least some conception of the fact that darker things exist. Right? You're comparing the hue of that salt to the conglomeration of all the hues of everything that you've ever seen in your conscious experience, in your life. And that goes for it terness. That goes for hardness, it goes with everything.