El alma humana, cuantas veces percibe las cosas según el orden común de la naturaleza, no tiene conocimiento adecuado ni de sí misma, ni de su cuerpo, ni de los cuerpos exteriores, sino tan solo un conocimiento confuso y mutilado

We are not at all to wonder [...] that we having but some few superficial ideas of things, discovered to us only by the senses from without, or by the mind, reflecting on what it experiments in itself within, have no knowledge beyond that, much less of the internal constitution, and true nature of things, being destitute of faculties to attain it.

Usually we think of our mind as receiving impressions and experiences from outside, but that is not a true understanding of our mind. The true understanding is that the mind includes everything; when you think something comes from outside it means only that something appears in your mind.

It is evident the mind knows not things immediately, but only by the intervention of the ideas it has of them.

I will only say generally, that in proportion as any given body is more fitted than others for doing many actions or receiving many impressions at once, so also is the mind, of which it is the object, more fitted than others for forming many simultaneous perceptions; and the more the actions of the body depend on itself alone, and the fewer other bodies concur with it in action, the more fitted is the mind of which it is the object for distinct comprehension. We may thus recognize the superiority of one mind over others, and may further see the cause, why we have only a very confused knowledge of our body, and also many kindred questions, which I will, in the following propositions, deduce from what has been advanced.

It would be indeed unusual if it turned out that the set of orders that our mind is able to construct and accept, having as it does a deep sense of “understanding the essence of things,” matches precisely the set of all possible orders to be detected in the Universe as a whole. We should admit that this is not impossible, yet it does seem highly improbable. This way of thinking, so modest in its assessment of our abilities, is probably the only way recommended, given our lack of knowledge, because we are not aware of our limitations.

The understanding, like the eye, whilst it makes us see and perceive all other things, takes no notice of itself: and it requires art and pains to set it at a distance and make it its own object....

If by this inquiry into the nature of the understanding, I can discover the powers thereof; how far they reach; to what things they are in any degree proportionate; and where they fail us, I suppose it may be of use to prevail with the busy mind of man to be more cautious in meddling with things exceeding its comprehension; to stop when it is at the utmost extent of its tether; and to sit down in a quiet ignorance of those things which, upon examination, are found to be beyond the reach of our capacities.

The mind is not only capable of knowing [innate ideas], but further of finding them in itself; and if it had only the simple capacity to receive knowledge…it would not be the source of necessary truths…

The human understanding is of its own nature prone to suppose the existence of more order and regularity in the world than it finds.

The eye sees only what the mind is prepared to comprehend.

The Eye Sees Only What The Mind Is Prepared To Comprehend.

If we follow whatever has so far taken shape, fully formed,7 in our minds, making that our teacher, who could ever be without a teacher? The mind (2:12) comes to be what it is by taking possession of whatever it selects out of the process of alternation — but does that mean it has to truly understand that process? The fool takes something up from it too. But to claim that there are (2:13) any such things as “right” and “wrong” before they come to be fully formed in someone’s mind in this way — that is like saying you left for Yue today and arrived there yesterday.8 This is to regard the nonexistent as existent. The existence of the nonexistent is beyond the understanding of even the divine sage-king Yu — so what possible sense could it make to someone like me?

A general limitation of the human mind is its imperfect ability to reconstruct past states of knowledge, or beliefs that have changed. Once you adopt a new view of the world (or of any part of it), you immediately lose much of your ability to recall what you used to believe before your mind changed.

It is a remark which needs no subtle reflection to make, but which we may assume that even the commonest understanding can make, although it be after its fashion by an obscure discernment of judgment which it calls feeling, that all the 'ideas' that come to us involuntarily (as those of the senses) do not enable us to know objects otherwise than as they affect us; so that what they may be in themselves remains unknown to us, and consequently that as regards 'ideas' of this kind even with the closest attention and clearness that the understanding can apply to them, we can by them only attain to the knowledge of appearances, never to that of things in themselves.