Cogito, ergo sum is the basic notion of "I think therefore I am" that Descartes used to prove the existance of the world. This Cogito was then broken by multiple philosophers (namely due to the fact that the statement "I think therefore I am" implies an unprovable identity due to the existance of I) and thus has left this proof as a way of looking at the world broken. Though, what hasn't been contemplated as much as it should is if there is still a world to be built from here, and I believe there there is. We can build ethics out of this broken state, a simple ethics, a subjective ethics, but an ethics none the less. Thoughts occour in the void, and those thoughts we know can be qualia. The qualia may not be associated with other qualia, but for certain we know there is qualia. Qualia by nature of itself has value attached, if you have the qualia of pain, it will be negitive. If you have the qualia of enjoyment, it will be positive. Due to this, we can construct an ethical system in where maximizing positive qualia experienced is a must. As all we know is thoughts (including qualia), we don't have any tangiable way to do so unless something further is constructed.
To generate further in the world, we must know there is a causer in the world. For qualia to exist, there must be something that creates it. It need not be representative of whatever reality really is, but we can confirm that something must exist to allow it. An effect without a cause is an unintelligible as there is nothing to justify it. A book floating in the air must have a reason for floating, if there is no reason it wouldn't float. If there is qualia simply there, there must be a reason for it, otherwise it wouldn't be there. So we can confirm another two thing to exist in a broken cogito: a causer of the qualia and an ethics based on the value of qualia.