As I see it we are able to think about 'past' or 'future' or 'everything' or 'nothing' or 'the unknowable' and so on because we possess symbolic language.
We also have memory and anticipation, which I think are also enabled, or at least greatly augmented, by language. I don't think this means that "the past or future can exist in our brains"; to me that idea doesn't make sense, so I see no need for an alternative. The reason I think it makes little sense is that past and future are just ideas. If they exist at all they exist as now, meaning that when the past existed it was present and when the future will exist it will be the present. Perhaps all moments are always physically existent, just not so for us we crawl through time.
So, I'm not being "resistant", I just don't see the reasoning that leads to your conclusion that "mental content is universally immaterial". I don't even know what that could mean, to be honest. But that's OK; we don't have to agree, it's just a matter of different perspectives.
I didn't mean to offend you by inquiring into your personal preferences. — Gnomon
You didn't inquire into my personal preferences, but spoke as if you knew what they were, and here you go again; assuming what my personal reactions are. But don't worry, I don't get offended by people in online exchanges, it's just ideas being exchanged, or ignored, or critiqued or whatever.
But, it's that "some other way" definition of immaterial that is controversial. Besides, on this Philosophy Forum, personal feelings about hot-button words are all too often the crux of argumentation on divisive topics, as opposed to dictionary definitions. — Gnomon
I don't see "some other way" as being uncontroversial, but as being philosophically useless unless it is explicated in a cogent manner. I haven't encountered any such explications, on here or anywhere else.
So, it's the emotional baggage attached to some words that make rational dialog difficult. — Gnomon
I'm not attached to any metaphysical views, but I realize that some, in particular those who have developed some kind of system or relate to some pre-existent dogma they are attached to, may have emotional baggage or investment in their ideas and beliefs. If you want to function fruitfully on this forum you would do well to drop such attachments and be open to learning new things. I'm referring here to the general "you" here, not you in particular, just to be clear.
I've seen quite a few people over more than a decade on these and other forums, touting the same set of ideas. like dogs who won't let go of their bones, and I'm astounded how attached some people become to their ideas. They are just ideas, for fuck's sake!
in order to communicate I need to know which implicit meaning of the term you are intending. To be explicit, when I use the term "immaterial" or "meta-physical", I'm referring to concepts that may be "unimportant" for scientists, but centrally important for philosophers. Are you approaching the topic from the science side or the philosophy side? — Gnomon
For me, 'metaphysical' denotes 'speculative ideas about the nature of things', which cannot be empirically tested or logically proven. As such, they may be interesting or not, fruitful for science or not. So, I agree with Popper that (some) metaphysical ideas are not unimportant for scientists, and I also think some metaphysical ideas may be important for some philosophers.
In general, though, I would say that only those metaphysical ideas which are informed by science can be important for philosophy as a whole, since Kant. So, for example, I don't think the idea of God is of much philosophical use these days, which is not to say that it could not be useful to some individuals in relation to their own personal philosophies; it's just that there are some things it is futile arguing for (or against).
So, to sum up, I don't see a division between the "science side" and " the philosophy side". Science informs us about ourselves, but it cannot answer all the questions that may be of importance to people, and it cannot prescribe how people should live either, but those are ethical, not metaphysical, issues.