Knowledge is vague , a simple statement easily explained.

Knowledge is based upon current pressumptions and opinions, since we only ever know what we know right now we can't be sure that it won't at some point in the future prove to be false or not as rigid as we at first thought.
Even "FACTS" of 100 years ago are ridiculed today as the posturing of the uneducated ,100 years from now we will probably be viewed in the same way.
Truth, fact, definate ,, I don't really buy it.
Question everything and take nothing for granted, impossible is simply a state of mind.

Then of course you have the question of perception, of course every person experiences things in their own unique way and since we can only ever be ourselves and imagining is not really real how can we truly understand something we can't experience, like how it feels to be a lab rat, we are told fish don't feel pain, how do we know that?
We barely have an understanding of our own bodies and brains.

As for the answer????? to my question as to which is most valid, I think you fail to understand the point I was trying to make.
The point is that academics are needed for different reasons than mechanics (PS my mate has no formal education he just knows bikes, he even struggles to read) and even without going to college or even finishing high school you can have a skill.