Can we doubt that we perceive?

We can even doubt that there is any such entity as "we." If we choose to.

We should not merely "doubt" it; we should "realize" that there is no "me", only the experience of the world, including an illusion of self.

So by your interpretation, doubt is a realisation of things that may not be what they appear to be... I can live with that, until I start doubting what I've realised.

No what I meant was we can be certain of something because we perceive. You can doubt what you percieve eg. the universe, reality, the self etc. but not percerption itself.

If everything is experiencing itself subjectively, what we are merely percieving is subjective experiences. But the funny thing about this is that the human mind is so powerful we can make these experiences seem 'real'. I also think that having certainty by way of our perceptions can be dangerous, cos people are lead into delusional thinking by an experience they percieved to be undoubtedly real.

We can't be certain by way of the actual experiences from our perception but the fact that 'we' perceive the world is proof of the experience. Whether the experience itself is believable or not is argueable.

Perception is perhaps secure to whatever extent that it has a definition(s) which escapes being dependent on reception. Thus surviving any doubt or nihilism about reception fostered by alternative views that do without such sensory inputs.

Leibniz's pre-Established Harmony would be an early example of a particular individual's experience of the world developing or unfolding without a literal reception of environmental energies or influences. His monadology featured a lawful-like coordination between the isolated experiences of beings so as to escape solipsism, but there were no intervening causal "forces" or mediating agencies that ensured this "harmony" (the coordination was pre-programmed as part of the unfolding presentation of reality stored in each monad).

Today, Leibniz's "windowless" approach to complex agents and primal units of consciousness would probably be framed in the context of holographic schemes -- where each part or element contained its own pattern/POV of the whole, while also being integrated with the whole. Rather than being a monadic thing-by-itself or partial precursor to Kant's things-in-themselves (the latter lacking the speculative claim of Leibniz's panpsychism and knowability of the internal constitution of non-human "things").

"Reception" (of a sort) was a possibility in Kant's approach, and he also eliminated Leibniz's figurative pretense of a relational space that the latter's version of things (monads) "dwelled" in. Which consequently collapses things into interpenetrating each other, from lack of dimensions separating them (space only being an organizing form of appearances, in consciousness). Things asserted their distinctness (freedom) while also being merged as one. Ergo, the "how" of Kant's "things" being able to influence each other minus a spatiotemporal organization being the case in his so-called "noumenal world" (i.e., minus causation), which causes otherwise conform to in Nature /appearances / experience. In the Intro to the CPR, Kant admits that he probably was not clear in some areas because of having to invent and grapple with new terminology, and appeals to contemporaries and future generations who "get" what underlies his approach to clarify any issues that arise.

We do not, indeed cannot, doubt what is immediate and unconditioned. What is happening right now, colors, sensations, feelings are unconditioned and immediate. What I add to them, e.g., evaluations, explanations, all interpretations are conditioned and mediate. A mirage, I like to say, is a real mirage but it is not a pond, that's an illusion, an interpretation.

Certainty of your senses is a necessary step in doubting them. If Descartes doubts his senses because a twig appears bent in water when in reality it is not, he is relying on his senses to tell him it is not bent in reality. Doubt of something presupposes certainty, thus universal doubt is not a viable option insofar as "nothing is certain" itself is an expression of a certainty, ie "I am certain that nothing is certain" is a contradiction.

Universal doubt of the senses furthermore involves a logical fallacy; the fallacy of composition. This is treating as universal a term that is really at least a particular: "this particular instance of sense experience was wrong" does not necessarily lead to "all sense experience is doubtful" because the most we can get from the first statement is "sometimes my sense experience is doubtful". We cannot say my sense experience is always wrong because we would have to rely on our senses to know they are wrong.

Does this answer your question?

Descartes relied on his senses to tell him that a twig LOOKS bent in water, not that it IS bent in water. The latter is merely an interpretive addition to his immediate experience.
The early Church taught us that all sensory experience was false and that only the faithful application of (Aristotlean?) reason led to truth. I'm claiming that sensory experience per se is reliable as far as it goes; reason may or may not assist in the proper interpretation of sensory experience.

I don't see how your distinction is pertinent. Surely Descartes was searching for truth and not appearances. He said we cannot trust our senses because there were instances when they were wrong.

We know our senses are reliable per se bescause otherwise there is no real knowledge, do you deny this??

Regarding the Early Church it depends what you mean be "early". There was conflict among philosophers regarding perception until S Thomas Aquinas, which was in the Middle Ages. Aristotle held the reliability of the senses and S Thomas echoed this.

I was not, of course, agreeing with the Church's derogation of the senses and my point regarding Descartes was an epistemological note regarding sensual information, not D himself. I tried to squeeze in D and the Ch. to no avail.
Your points are all valid.

Ok, I see. That's understandable considering the Church has had various philosophers proposing differing views on perception.

Regarding your answer to this question which was selected, do you think you could you expand on it if you have the time?

Thanks for clearing up the confusion in my previous post. I don't doubt sensory information, but I do doubt the interpretation our minds make. To me, these things are still debatable.

So you don't doubt that you see "white", but you doubt that you correctly judge a thing to be white, correct?

If so, then my question is this: do you follow Kant when he says that all we can know are sense impressions but not things themselves? Do you think sense impressions are the farthest we can go with knowledge and that we can never apprehend essences?

I came across one idea that stated that the human brain receives millions of bits of information in a continuous flow, and that only a fraction of it is perceived as reality.
Information from different sources (senses) that contradict each other is simply ignored by the brain, as it's purpose is forming a coherent continuation. Only information that goes towards supporting this coherency is included in what humans refer to as reality.

I am sorry to say that I do not recall the source of this idea.

I do not doubt my IMMEDIATE experience. I may not have absolute certainty that it is what we call "white", white-ness is an ascription that may be based on delusion--unlikely* but conceivable, and THAT may be delusion as well. But the actual SENSATION is undoubted. Even if it were an hallucination of whiteness it is an actual experience nevertheless. (a mirage is a real mirage but not a real pond)

*This probablistic consideration indicates that there is no practical problem, but we are talking about philosophical (hypothetical, theoretical, absolute, abstract) certainty.

Ok. So you don't have absolute certainty that a thing is white, it is only probable. Right?

By "ascription" do you mean that the whiteness comes from us and is imposed on the thing or that whiteness is actually in the thing and is merely passively received by the sense organ (the eye)?

Also, if you are saying that error only occurs in the mind and not in the act of sensing, then I think Aristotle would agree

It depends what you mean when you talk about essences. In my mind I'm not sure essensces exist in an archetypal sense, but I do think there is some relative experience we share when learning the same things, and most likely it would be different for each individual. I don't necessarily think that sense impressions are the be all and end all to knowledge per se. I think it is interesting that we use metaphors for things we otherwise cannot rationally explain any other way, but this does not mean what we learn from these metaphoric justifications is correct. In my view, it just helps get us around. So when I see 'white' I don't really doubt it is 'white', but the fact I can't explain why 'white' is 'white' or scientifically differentiate the sub-atomic quanta of the colour white with some other shade or colour, means I can still doubt what it is, even if my sense impressions and 'knowledge' of the matter tells me otherwise.