Not always: one can always know their own existence. Mathematics and logic can also be argued on. I also think the context matters, as some information can be said to be infallible with specific premises, like that we can generally speaking trust our perceptions. Considering "I think, therefore I am" to be the only certainly justified belief and the only infallible knowledge won't get one far and I think no meaningful conclusions can be drawn from that. — BlueBanana

But of course one can always fallibly know about one’s own existence, that 1 and 1 equates to 2, etc. In your statement though I read the implicit affirmation that knowledge is infallible in order for it to be real/true knowledge. Reminds me of my take on why so many philosophical skeptics in history maintained that there can be no knowledge: because to others knowledge is always taken to entail infallibility.

To be clear, by “infallible” I don’t intend “infallible for all intended purposes” of “infallible given the conditions X, Y, and Z” but, instead, that which is “perfectly secure from all possible error”. I duly uphold that the argument for the law of noncontradiction is abnormally strong to an extreme—or at least that it can be—but I as of yet don’t know of an infallible justification for it. Because there is no justification that is perfectly secure form all possible error that either you or me (or anyone else that we’ve ever heard of) can evidence for the law of noncontradiction, the law of noncontradiction then will not be perfectly secure form all possible error as far as we can evidence. It is thereby fallible—i.e. holds some capacity of being wrong, regardless of how miniscule and utterly insignificant this capacity might be. Which is not to say that it is therefore false.

Then, 1 and 1 being equivalent to 2 could potentially entail that 1 and 1 does not equate to 2 at the same time and in the same way. This is acknowledgedly aberrant. But since there is no infallible justification for the law of noncontradiction, contradictions could then be instances of non-erroneous reasoning in ways in which our limited (non-omniscient) minds can’t currently fathom. This is my short-cut argument for 1 + 1 = 2 being fallible—and not infallible—knowledge (for it could be that 1 + 1 is also not equal to 2 … iff contradictions were not errors of reasoning … which we can’t infallibly evidence one way or another). This, though, doesn’t make it untrue that 1 + 1 = 2 and only 2. Our notion of 1 + 1 = 2 could well be an ontic truth, and thereby infallibly correct, but I’m not holding my breath for anybody to demonstrate its literal infallibility.

As to Descartes’ cogito ergo sum, Descartes took the “I think” proposition for granted, without demonstrating its infallibility. In fact, the thought he refers to could conceivably be caused by some given other than himself—the “I” he is addressing—such as by the evil demons we’ve all since Descartes time have become so accustomed to … or else the thoughts could be utterly uncaused in all senses (a block-universe model could account for this). Were any of these alternatives to describe that which is true, the proposition “I think” would then be false. As with 1 + 1 = 2 however, this isn’t to say that “I think” is therefore false. But it is not an infallible premise, or proposition, or conclusion form which other infallible conclusions—namely, that of “I am”—can be drawn.

In short, knowledge pertaining to non-omniscient first person points of view will always be fallible, regardless of what it may be about. I can argue this one further if needed. Simply present an instantiation of what is supposed to be infallible knowledge. :razz:

Though, because justification can be strong and weak, so too can knowledge be strong and weak. We hold strong knowledge that we are earthlings (right up there with BIVs, say rather than all 7(?) billion of us being extraterrestrial offspring) … as well as that 1 + 1 = 2 and that we are/exist. We hold comparatively weak knowledge of what the weather will be like in a few days from now (but we generally still know something about it).

That all knowledge is theoretically capable of being wrong, again, does not then mean that all our knowledge therefore is wrong (it could in fact depict that which is ontically true). Only that it is fallible, sometimes to an exceedingly insignificant degree—this outside of philosophical contemplations such as those regarding the nature of knowledge.

What about the situations where people might disagree on whether the evidence justifies a belief? — BlueBanana

In these cases, these very same people would disagree on whether or not knowledge is had. My quoted statement states that where knowledge is had it will always be (fallibly) epistemically justified to be true. Where there is disagreement about the validity of justification, however, there will then also be disagreement on there being knowledge.

If the Russell's teapot existed there'd be no justification for individuals of it. — BlueBanana

A good point. Poorly worded on my part. Here I meant that truths are always justifiable in principle. For example, if a teapot floats in space between the Earth and Mars, it will be capable of being evidenced to so be given a sufficiently large body of acquired information and analysis of this information. So too with there being a needle in a haystack. But, yes, we were talking in context of knowledge being justifiable true belief in practice. What I was getting at, in retrospect, is a little more complex, and it deals in large part with what I take to be ontological themes. To not seem like a charlatan: Ontic givens will, I uphold, not be mutually exclusive (will not be contradictory) and will cohere with each other when sufficiently related … akin to saying that the cosmos is a whole (it in fact gets more complex due to ontic randomness/indeterminacy being, imo, part of the picture, but to keep this on the brief side …). Truths, then, by virtue of conforming to ontic givens in one way or another, shall then hold similar properties: they shall not contradict and will cohere when sufficiently related. I won’t try to justify this here; its more than a mouthful even if I haven’t missed the mark. But then, if so, to justify a truth is to show how it is noncontradictory to other established truths (with those of direct experience being paramount, though fallible; here invoking foundationalism) and, with this, how it coheres into sufficiently related truths (here invoking coherentism). So truths are then always justifiable, at least in principle. But, in retrospect, my bad for bringing this up. It’s a topic for a different thread, maybe. And, again, good call on what I previously said. Yes, some beliefs which are ontically true cannot be justified in practice.

First I'd like to say that the hollow Earth theory is a poor choice of example [...] — BlueBanana

I personally like the hollowed Earth example. The Earth is either hollow or it is not; they can’t both be true (and even if contradictions were to be non-erroneous reasoning, we wouldn’t be able to make any sense out of them anyway). Even when knowledge is specified as “believed to be true beliefs epistemically justified in being ontically true” it would still pivot around ontic truth … thereby being upheld to be justified true belief (till evidenced to in fact be untrue, were such time to ever present itself … it might never do). It could be that my expressions/understandings are off base—in which case I’m very grateful for the criticism—but, to me, propositional knowledge then entails that that which is known is always assumed to be ontically true. Then, because those who know the earth to be hollow hold contradictory positions to those who know the earth to be solid, at least one of these two maintained instances of knowledge will be false. Justifications for the Earth being solid far outweigh justifications for the Earth being hollow (e.g., tectonic plate movements caused by convection currents of magma explain earthquakes … earthquakes being something which the hollow Earth model cannot as coherently justify).

Now that I think of it, this turns out to be a fairly good example of the complexities involved with knowledge. But I’ll leave it as it is unless there’s greater interest in this example.

More on topic, I find the view peculiar in that it allows false knowledge but does not really allow its practical usage. Basically it gives individuals the possibility of belief that their knowledge has a chance of being incorrect, but the hollow Earth model is, although stupid, like the idea of evil daemon deceiving us, theoretical possibility, like the idea of evil daemon deceiving us. This is why I'd prefer to define irrational beliefs, when believed by other to be justified, to be knowledge, that one then has a belief about that the knowledge is false. — BlueBanana

I’m so far not getting this. While I haven’t myself explicitly made use of the phrasing “false knowledge”, I can understand it in this way: false knowledge is not knowledge because it is false. This in parallel to a false truth (e.g., a lie) not being truth because it is false.

That seems logical but I also can't quite agree. I feel like there's a jump between the colloquial sense of uncertainty and absolute certainty. — BlueBanana

My take is that if we don’t find a means to amalgamate common sense uses of certainty (as in, “I’m sort’a certain that […]” or “my certainty of […] is strong”) with philosophical certainty, then we deprive ourselves of a term (and corresponding concept) used for “not being uncertain about” within realms of philosophy of mind. What I meant was that to believe X is to not be uncertain about X (therefore, to not be uncertain that our beliefs concerning X are true)—and not that it means “believing belief X to be (philosophically/absolutely) certain”.

... And now, without further ado, I'm off to bed. Man, I'll try to keep my posts shorter next time around. No promises though.

Sorry about the snarky comment. As I said, it wasn't about you, personally.

I might be willing to take "something exists" or "at least two things exist" as a starting point. Moving on, we have come to understand that many things exist. So I am not willing to entertain that idea as an account of reality. — Bitter Crank

Okay thank you.

By the way to say that “at least two things exist” is not to say that “only two things exist”, and so is not to say that “many things exist” is false. A lot of existence can be understood as a duality, but it doesn’t imply that the duality is all there is. For instance there can be many beings on each side of the duality.

I suppose one could claim that the universe, and the fullness thereof, resides in the single consciousness of God. If so, God seems to have thought a very complex reality made up of many parts. The problem with this theory is that we do not have the means to parse the consciousness of God, if God exists in the first place. Still, the universe as the dream of God has a certain aesthetic appeal and weightiness. — Bitter Crank

Indeed that’s one possibility, and one I ascribed to for a little while, however one wonders why would this single consciousness dream or imagine so much suffering if it could imagine anything. In another thread I hypothesized that it would dream suffering because it is eternally alone and suffers from this loneliness which it tries to forget, however loneliness doesn’t necessarily imply suffering, loving oneself makes one feel not alone. So if all there was is this single consciousness, we are left wondering whence suffering?

And even if we say that only this single consciousness exists, as soon as it dreams something there are at least two things that exist, the consciousness and what it dreams. And even if we identify that consciousness with what it dreams, as long as we can distinguish things within this dream then at least two things exist. Whatever assumption we start from always leads to the conclusion that at least two things exist. I’m sure I’m not the only one who has reached this result but I never heard it before.

Descartes gave the Cogito ergo sum (“I think therefore I exist”), which was criticized because his reasoning only proves that “something exists” (or “thinking exists”), however we can go further than that and say that “at least two things exist”. That’s something we can use as a secure foundation for knowledge, rather than the mere “something exists”.

And when we consider that there is a fundamental duality at the heart of this existence we can come to explain a lot of things that otherwise don’t seem to make sense. But of course we don’t have to assume a fundamental duality (we could assume a trinity or a multiplicity), and even if we assume a duality this doesn’t imply that only two things exist (we can see many things existing on each side of the duality).

However it is interesting to notice the duality between attraction and repulsion, unity and division, connection and separation, understanding and indifference, love and hate, we can explain so much by seeing existence as a struggle between two forces, one which acts to unite/attract/connect and one which acts to divide/repel/separate. Especially when we notice that unity/attraction/connection is associated with positive feelings (love, beauty, happiness) whereas division/repulsion/separation is associated with negative feelings (hate, ugliness, suffering).

I believe that in this way we can come to a unified picture of existence, where emotions are not a mere byproduct of motion but are as fundamental, where emotion and motion are two facets of a more fundamental thing. I believe that only in this way we will come to a unified understanding of existence, and not by seeing emotion as a byproduct of motion, as stemming from laws of physics or motions of particles or brain states, as is customarily believed in the materialist picture which appears to lead into an impasse.

I think Kant's argument comes into play when metaphysical conclusions are drawn on the basis of methodological axioms - in other words, when arguments are made about first philosophy on the basis of scientific naturalism.
— Wayfarer

On naturalism, the methodological assumption of naturalism is reflected back on itself (i.e., as the study of the study of nature). So why would that be a problem and how would Kant's argument be relevant here? — Andrew M

'First philosophy' or metaphysics is concerned with the ultimate nature of reality. In a theistic metaphysics, then God is understood as being the source or ground of being. A naturalistic philosophy doesn't countenance such an idea as God is (by definition) super-natural, 'above' or transcendent to nature. So the attitude generally is, whatever hypothesis you want to consider, it can't include something which is by definition above and beyond the naturalist framework- which is what I'm calling 'metaphysical naturalism'. You see in many atheist arguments (including many posted here) that science proves or at least suggests that the world has a naturalistic explanation or can be thoroughly understood in naturalistic terms and that there is nothing outside or above or transcendent to nature in terms of which understanding ought to be sought.

This is where Kant is relevant - recall that he said that a central goal of his critical philosophy is to 'discover the limit to knowledge so as to make room for faith'.

I'm arguing that is that it is possible to pursue a naturalist account while still understanding that it has limits in principle - that the naturalist account is not all there is (which is what I understand Kant to be saying.) That is what I mean by distinguishing methodological from metaphysical naturalism - the former sets aside or brackets out metaphysics in pursuit of the naturalist account. But it doesn't necessarily say anything about what if anything might be beyond that. It's close in meaning to Huxley's agnosticism.

In other words [Kant] is rejecting naive realism, but not scientific realism, which if it is at all reflective, acknowledges that we are only examining and conjecturing about the world as it appears to us (obviously, since the acts of examination and conjecture cannot deal with anything but what appears). — Janus

I think many scientific realists would either not be sympathetic to Kant, or wouldn't understand his critical philosophy. Some would but it would not be uniform by any means. (What was the wisecrack Richard Feynman made? That philosophy of science is about as useful to scientists as ornithology is to birds?)

Consider the point in this thread where I brought this up - it was the quotation by Andrei Linde about the 'role of the observer' in understanding the nature of time. Linde is a physicist and cosmologist, responsible for a lot of the current theory around big bang cosmology:

The passage of time is not absolute; it always involves a change of one physical system relative to another, for example, how many times the hands of the clock go around relative to the rotation of the Earth. When it comes to the Universe as a whole, time loses its meaning, for there is nothing else relative to which the universe may be said to change. This 'vanishing' of time for the entire universe becomes very explicit in quantum cosmology, where the time variable simply drops out of the quantum description. It may readily be restored by considering the Universe to be separated into two subsystems: an observer with a clock, and the rest of the Universe. So the observer plays an absolutely crucial role in this respect. — Paul Davies, The Goldilocks Enigma

So, I'm arguing that this point is basically Kantian - that it acknowledges that time doesn't exist independently of the observing mind; where there is measurement, there is mind, and that also goes for the naturalist understanding of the early Universe. And this conforms with what I understand Kant to be saying:

The transcendental idealist, on the contrary, can be an empirical realist, hence, as he is called, a dualist, i.e., he can concede the existence of matter without going beyond mere self-consciousness and assuming something more than the certainty of representations in me, hence the cogito ergo sum. For because he allows this matter and even its inner possibility to be valid only for appearance– which, separated from our sensibility, is nothing – matter for him is only a species of representations (intuition), which are called external, not as if they related to objects that are external in themselves but because they relate perceptions to space, where all things are external to one another, but that space itself is in us.

(A370)

which he contrasts with 'transcendental realism':

The transcendental realist therefore represents outer appearances (if their reality is conceded) as things in themselves, which would exist independently of us and our sensibility and thus would also be outside us according to pure concepts of the understanding.

(CPR, A369)

I know I'm not a Kant scholar but this particular point is central to what he described as his 'copernican revolution in philosophy', that 'things conform to thoughts, not thoughts to things'. I'm not making any point beyond that.

Punshhh
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↪Frank Apisa I agree with you when it comes to questions about the unknown. I don't use the word believe, for the same reasons you give. However I have no issue with the philosophy of epistemology. Jtb is appropriate for philosophies which address human issues, humanities, politics etc.

But this thread is not about that, it is about certainty, the certainty of reality. So jtb is irrelevant and we both have to rely on logic and a kind of thinking which ignores human issues, beliefs and ways of thinking. — Punshhh

Thank you, Punshhh.

The indiscriminate and careless use of "believe/belief" is annoying in most forums (fora), but in a forum devoted to philosophy, it goes way beyond annoying for me. That is the reason I raised the issue. Apparently the point is lost on those who prefer not to see it.

This leaves me at the position expressed in this phrase. "I know, therefore there is something" — Punshhh

That is also where I am with regard to the Cogito, ergo sum suggestion, P. I am astonished it is not seen and acknowledged as readily and as widespread as it should be.

"Cogito Ergo Sum". According to prof John Cottingham (Reading) in the "Oxford Companion to Philosophy" this is perhaps the most celebrated philosophical dictum of all time. Perhaps someone on this forum feels like doing a master's dissertation on the topic - especially if the era of the Enlightenment is what turns you on! — Daniel C

I'm sort of working my way through it with all my answers on this thread right now. It should qualify in any sensible official regard. I'm not much for the prevalence of authorities.

Philosophy isn't a subject so much as an activity, in which muddled ways of saying things are exposed and analysed. — Banno

Spot on.

To be more precise it is a mind activity. An activity of expressing your mind. The output of philosophical thought is information about the mind activity of the philosopher.

So:

Philosophy is an expression of human consciousness ( mind activity ).
Philosophical work is information about the mind activity ( consciousness ) of the philosopher.

This I take to be self evident, but some people don't get it until they are asked to produce a philosophical work that is not an expression of the philosophers mind activity! - not logically possible.

The question becomes can philosophy produce more then an expression of mind activity?
In a related thread - what is certain in philosophy? - the outcome was - Cogito, ergo sum.

But: I think therefore I am is information about the mind activity of Descartes.
It is an expression of his consciousness!

To confound things a little.

Art is an expression of human consciousness.
Art work is information about the artist's consciousness.

This idea of the power of belief has come to its logical conclusion for me.

Lately I've begun to realize and understand that we are our beliefs. Our beliefs are the entirety of our being. One can understand this completely, and yet, trying to elaborate what these are, find them either trite and mundane, or nebulous and elusive, hard to pin down or specify.

And so they should be. Heidegger says "the more comprehensive a concept is in its scope...the more indeterminate and empty is its content" (Introduction to Metaphysics, p. 43) So, in fact, knowing that beliefs are the basis of being, we reach the point of the pure indetermination of content. I know that I am both the product and the author of my beliefs. I know that I exist. Cogito ergo sum.

Relative to another thread, for example, this would explain why people need religious beliefs; they need religious beliefs to found their being when they themselves are incapable of doing so. Either you assume responsibility for your own being, or you accept a whole lot of doctrinal gibberish that does nothing to fill in the gaps between obeyances.

Glory, for the Greeks, is the highest manner of being....Glory means doxa [which is "belief"]....I show myself, I appear, I step into the light. (Introduction to Metaphysics, p. 108)

The being of believing, the being of believers, the being of belief.

Why do we need justification for beliefs? That's why they are beliefs. They are unjustified knowledge.

If you want justified knowledge, that's a bit impossible. As per the proof. In empirical cases. Although "cogito ergo sum" is a justified empirical statement proving the self's existence to the self, and to nobody else.

But why is "Albert not the same as Albert" an unjustified wrong statement? Language perhaps, as the unjustified conveyor of thoughts, is the culprit that we object to? Is language an unjustified conveyor of thoughts? Well, the Chinese room experiment is a proof of that. I mean... you need language to disjustify the valid existence of a priori proofs expressed in language.

That's a bit too rich. Because then we get to the paradox (and not merely a contradiction) of @Amalac. The proof of proving all proofs wrong proves itself wrong... therefore all proofs are not wrong... including the proof in the trialemma; then it means the trilemma is not wrong... which means it renders itself wrong if it's right, and it renders itself right if it's wrong.

Truly a clear paradox.

So if yo don't want to go insane following a paradox, don't start reading this thread.

There's 'objective' as in 'true for everyone' and there's 'objective' as in true in the absence of a subject. For me they're indistinguishable — Isaac

Very good. This is a properly philosophical question. But think about that. Whatever is true 'in the absence of a subject' is by definition unknown. In fact I'm going to call into question that there is a domain of facts that exist in the absence of any subject.

You said before that

as 'science' has proven, measurements of the way the world is are observer dependant. — Isaac

I think that's an over-simplification of the 'observer problem' but it's still relevant to the point.

I think that the presumption that there is a domain of fact that exists irrespective of anyone's knowledge of it is what is described in Kantian philosophy as 'transcendental realism'. This is the belief that 'the world' has an instrinsic or observer-independent reality which we discover or uncover - an observable reality that transcends our knowledge of it. It's the sense that there's a real world 'out there' which you and I both dwell in but which is real irrespective of our knowledge of it:

The transcendental realist therefore represents outer appearances...as things in themselves, which would exist independently of us and our sensibility and thus would also be outside us according to pure concepts of the understanding. — Kant, CPR A369

But remember, we're taking philosophy here, not empirical science. We're dealing with foundational issues in the nature of knowledge. And I think what you're appealing to as 'objective in the absence of any subject' is just the common-sense view that the world is real independent of any act of observation. That is just what has been called into question, in some contexts, by quantum physics; see this post.

So "not objective. But real" doesn't make any sense as a claim. — Isaac

It doesn't make any sense to an empiricist. But consider the nature of mathematical objects, such as number. Mathematical proofs and the like are not objectively true, they're deductively true. I think as mww already said earlier in this thread, the metaphysics of being is more like that, than like an empirical proposition. So let's say there's an empirical domain, the domain of phenomena, which is what appears to us; 'phenomena' means 'what appears'. But what is the nature of mathematical reasoning? What of the inner processes of judgement, that we use all the time to arrive at conclusions about the nature of things? I don't see that, and many other facets of reason, as being empirical in nature. That's where I think a form of dualism is defensible.

Interestingly, Kant himself acknowledges that he is a dualist in this passage:

The transcendental idealist, on the contrary, can be an empirical realist, hence, as he is called, a dualist, i.e., he can concede the existence of matter without going beyond mere self-consciousness and assuming something more than the certainty of representations in me, hence the cogito ergo sum. For because he allows this matter and even its inner possibility to be valid only for appearance– which, separated from our sensibility, is nothing –matter for him is only a species of representations (intuition), which are call external, not as if they related to objects that are external in themselves but because they relate perceptions to space, where all things are external to one another, but that space itself is in us. — Kant CPR A370

If it's not a fact about the world then what is it a fact about? Shouldn't require an essay to answer. — Isaac

It might, if you're not seeing the point at issue! There is an enormous volume of literature on just these kinds of questions. Many books have been written on it.

Honestly, hand-on-heart, not trying to be confrontational or condescending, there really is something you're not seeing in this argument. What it takes is a kind of shift of perspective, something like a gestalt shift.

Yes. That's a way to look at it. Howeve, please allow me to say that 1) I present solid and extensive arguments --and new each time-- based on examples and real experience and 2) I also present similarly valid and grounded arguments agsinst your statements, etc. On the other hand, I can't see the same thing from your part. You seem not even try. It looks like you just or mainly stick to your views, without defending them approriately. — Alkis Piskas

This is just a your personal (rather self-centred imo) view Alkis, for me, it has no value beyond your personal complaint. You wont be surprised that I also don't agree with it's proposals.

bringing in external "help" from other people and esp. providing me with links to interviews etc., well this not at all my cup of tea nor I find it effective. — Alkis Piskas

The same thing was believed by Heraclitus 2,500 years ago! — Alkis Piskas

Einstein himself said that time is an illusion, and more precisely: "The past, present and future are only illusions, even if stubborn ones." — Alkis Piskas

Was your use of Heraclitus and Einstein above, you bringing in external help, contradicting your own position?

You see, this lack of expanding and supporting your personal views prevents me from seeing the foundations of your viewpoints, which could mabe allow me to view myself the subject from a different angle and with additional data. In fact, you deprive me of that pleasure! :smile:
Well, this is howI view this exhange myself, of course. — Alkis Piskas

I accept that the above, confirms that this is how you view our exchange on this thread.
That has little meaning for me, as I don't see our exchanges as competitive, I see them as interesting.

Challenge: Prove (show) to me that time is physical and thus it exists and it is real.
In a new unit of time. Forget all we have said. — Alkis Piskas

The term 'physical,' described as:
1. Relating to the body as opposed to the mind:
2. Relating to things perceived through the senses as opposed to the mind; tangible or concrete:
"the physical world"
SIMILAR: material, substantial, solid, concrete, tangible, palpable
3. relating to physics or the operation of natural forces generally: "physical laws"

Physicists define time as the progression of events from the past to the present into the future.

Your physical body in the reference frame of its own existence, (cogito ergo sum), in your own personal reality, materially, tangibly and palpably, experiences progressing from the past, to the present to the future. This can be empirically demonstrated by observing you over any notional time unit you wish, from sand clocks, sundials, water clocks to atomic clocks. (The base unit of time in the International System of Units (SI), and by extension most of the Western world, is the second, defined as about 9 billion oscillations of the caesium atom.)

I understand the proposals that time is an emergent property, rather than 'physically' real, but I think such notions are similar to all 'Plato style' 'idealistic' notions, such as the ideal clock or an ideal measurement etc. There is no biggest or smallest, or any real example of nothing/infinite/perfect. These are simple placeholders, for notions that have no actual existents and can only ever be asymptotically approached. WE (as an example of self-aware existents,) make time and distance real, and for me, any proposals from real physics or metaphysics, that time and distance are not real, remains, currently, of little significance or value. I remain open to the possibility, that such notions, if irrefutably confirmed, will become significant and gain value in the 'dare I say,' future.
It does not matter if you do not change your position regarding time, based on anything I have offered in our exchange here. The truth of what time is, exists, regardless of whether or not you, I or anyone else, currently, has correct knowledge of it.

So it must be P -> Q = Not P or Not Q — Corvus

(p→q)↔(¬p∨¬q) is invalid.

P -> Q is FALSE. — Corvus

No, it's invalid. It can still be true under some interpretation. It can also be false under some other interpretation.

But of course, that you have not shown the cogito to be invalid does not imply that it is valid. @flannel jesus has not shown that the cogito is valid - if indeed that is their supposition.

_______

The catchphrase "I think therefore I am" of course is not a proper syllogism, and it doesn't have to be, the complete argument is:
Thinking → existing
I think
Therefore I exist — Lionino

It's not a proper syllogism, yet you present it in syllogistic form? Make up your mind: is it an inference, or not?

That every single philosophical argument needs to be put in syllogistic shape is a fantasy. It is more than impressive that cogitō ergo sum, the crowning achievement of the father of modern philosophy, needs to be defended against so many bad arguments in a philosophy forum. — Lionino

Is it a valid inference, on which we must all agree, or is it an intuition, a mere hunch or impression?

_______
Underpinning the whole of this thread is the misapprehension that we can only know stuff if we are certain of it, if our belief is indubitable.

This error leads folk to conclude either that we must build our knowledge from solid foundations, such as the Cogito, or else that we do not "truly" know anything. Both views are muddled.