In what sense are you using the word "epiphenomena", then? Wikipedia provides several definitions across various domains [0] none of which appear to match the way you're using it. It even states that "charge and current are 'epiphenomena'" according to Maxwell.
Your description
> aggregate to an apparent quantity that doesnt correspond to anything in the world
is unclear. What do you mean by "the world"?
You go on to say
> There is no property of animals called, "forgetting"
It feels possible to me that a sufficiently complex model of the brain can observe an individual and determine that they are in a state of "forgetting". Not with current technology, of course, but I don't see what rules it out in principle.
Likewise, I don't see why it's impossible for mental states to be reduced (with sufficient computational power) to the states and interactions of the brain's constituent atoms.
Say there are formula whose terms correspond to individual causal properties of a system, whereby action on one of these terms necessarily brings about a determinate response in another, eg., f=kQq/r^2... if I increase one of the charges, necessarily, the force increases. There is a sense in which a highly specific explanation of "electrostatic force" includes "charge", so that deabstracting this formula would yield a logically necessary structure.
Then there are formula on the other end, "teen mazagine regressions", where the terms are superstitious aggregates (eg., star signs, number of times you've kissed, etc.).
And formula/models/etc. inbetween, where terms like 'temperature' correspond to a property that no part has, but there is a "nearly determinsitic" relationship between them, such that necessarily for any given set of measures (x, y,t) you have a temperature.. but that you cannot, in practice, actually set {(x, y, t)} so you have a "stochastic-causal relationship".
My claim is that almost all pscyho-social science is of the teen magazine variety: running linear regressions on surveys and then falsely attributing reality the apparent property given by the correlation coefficient. This is just outright pseudoscience and why much of this stuff is unreporducible nonesense.
There is nothing even like "temperature" to our mental faculties, which if explained with a scientific theory, would comprise a vast number of specific causal properties. To say we "forget something" is to describe a combination of 100s of processes each of which have different ecological expressions.
Likewise, "IQ" is exactly the same sort of psuedoscience: a linear regression through survey responses of an entire population and then a fraudulent pseudoscientific project of taking this correlation coefficient and turning it into a singular mental faculty. 110% BS
I sort of see what you're trying to get at, but I think you're making some fairly strong ontological commitments regarding physical properties. If we take a step back and try not to assume any ontologies, a "property" of a system can be functionally defined as a measure that can be reliably observed and recorded in a well-defined experiment. For example, someone's Memory Span [0] is a property of their brain at a given point in time. There are replicable studies measuring the relationship between memory span and other properties like age or speech rate.
Sometimes it's possible to encode the relationships between these properties using mathematical equations that are falsifiable via experiment. But this isn't what makes something physics. Physics is simply the process of applying this approach to matter, energy and force. I mean, I admit that experimental psychology isn't physics. And we don't yet know the mechanisms well enough to have a model that reduces to fundamental interactions. But it's not far off the way that mathematics is (successfully) used to measure and predict phenomena in other scientific fields such as biology.
Your description
> aggregate to an apparent quantity that doesnt correspond to anything in the world
is unclear. What do you mean by "the world"?
You go on to say
> There is no property of animals called, "forgetting"
It feels possible to me that a sufficiently complex model of the brain can observe an individual and determine that they are in a state of "forgetting". Not with current technology, of course, but I don't see what rules it out in principle.
Likewise, I don't see why it's impossible for mental states to be reduced (with sufficient computational power) to the states and interactions of the brain's constituent atoms.
[0] https://en.wikipedia.org/wiki/Epiphenomenon