How could all people be inherently wise? What about psychopaths, or the simply stupid? In Buddhism we say that most of us live in ignorance of this inherent wisdom which is obscured by our ignorant and misguided thinking, never the less this wisdom is still present. This sets Buddhism apart from most other religions in believing that all people have an inherent goodness even if their behavior doesn't show it.
What the Buddha discovered is that if we simply clear our minds of our ignorant thinking then a clear mind will emerge with the most basic understanding of our place in the Universe. This is the wisdom which we all have even if normally obscured. Of course clearing our minds of our ignorant thinking is not simple, It may be a simple idea but not simple to actualize, that is why we practice and practice and practice. And it is not so simple as just learning to stop thinking for a few moments in meditation, though this is getting close. But then when it happens, and it is usually quite dramatic, the mind of wisdom will emerge which is quiet, and joyous, and humerus, filled with love and compassion, and a completely different understanding of things. This is the awakening of bodhi. This is the awakening of prajna.