At the most fundamental level, are Pain and Pleasure the only real things we perceive? — Mehdim

We don't perceive pain and pleasure. We interpret certain sensory information as painful or pleasurable. Avoiding pain and seeking pleasure are motivations for action.

So, let's change the question - Are avoiding pain and seeking pleasure the only motivations for our actions? That just sets up a circular argument - We define pain as something we are motivated to avoid and pleasure as something we are motivated to seek.

We don't perceive pain and pleasure. We interpret certain sensory information as painful or pleasurable. — T Clark

What’s your distinction between interpreting and perceiving here?

Pleasure vs. pain is too reductionistic. It is probably the case that single celled organisms operate on so simple a basis, moving toward food and away from averse stimuli. Simple organisms probably operate on a similar level. C. elegant has about 900 cells in total. They are far more complex than single-celled animals (or plants); they have about 200 neurons in their bodies. Large animals have far larger brains and can operate at a higher level than a binary + vs - stimuli.

Of course, you can wield an ax or a chainsaw and divide the pile of all possible experiences into + or - , but that seems pretty crude.

When we walk down the street, the most basic evaluation we make of other people is "A Potential",
"A Competitor", or "Irrelevant". That's a three way split.

When you look at the menu in your favourite restaurant, you have to choose among perhaps 5 favourite dishes, all very pleasant. Then there is the competing issue of cost. You might like the steak tartare, but it costs 3 times as much as the stuffed grape leaves which you also like. Your date is a vegan, so splitting the steak tartare is out of the question (you won't have to give so much as a bite of it). The desserts are good too -- Galatopoureko (custard baked in filo crust) isn't vegan so you won't have to share that either.

You have quite mixed feelings about your date. We won't go into all that, but at least it is a lot more than a simple split of pleasure and pain.

There is no need to reduce everything to a + or a - . It serves no useful purpose.

Aristotle noted that matched pairs of qualities collapse into single things like unhappy couples at a wedding.
Keats noted that truth is beauty.
I think they were at the same event.

Do you know any website or other sources which i can learn more about the principle of pain and pleasure?

When you look at the menu in your favourite restaurant, you have to choose among perhaps 5 favourite dishes, all very pleasant. Then there is the competing issue of cost. You might like the steak tartare, but it costs 3 times as much as the stuffed grape leaves which you also like. Your date is a vegan, so splitting the steak tartare is out of the question (you won't have to give so much as a bite of it). The desserts are good too -- Galatopoureko (custard baked in filo crust) isn't vegan so you won't have to share that either. — Bitter Crank

To me these are all pain/pleasure related considerations. For example:

1. 'choose among perhaps 5 favourite dishes, all very pleasant' - equal pleasure for all dishes
2. 'Then there is the competing issue of cost' - expense now denies pleasure in future (money=pleasure)
3. 'You might like the steak tartare, but it costs 3 times as much as the stuffed grape leaves which you also like.' - then the question is do you get 3 times or more pleasure from the steak tartare as the grapes.
4. 'so splitting the steak tartare is out of the question' - lack of ability to save money = lack of future pleasure
5. 'You have quite mixed feelings about your date' - companionship and sex are all about emotional and physical pleasure in the short/long term

It all really just comes down to hedonism IMO. Its a matter, though of getting the definitions of pleasure and pain right:

- We have to include all forms of pain/pleasure - physical/emotional/intellectual/spiritual
- Long and short term must be considered (long term pleasure/pain outweighs the short term)
- The impact on your peer group must be considered (if it is painful for your peers, that will be reflected back upon you).

I think of it in terms of maximising net pleasure (total pleasure - total pain) for oneself (which entails maximising net pleasure for one's peer group).

I believe this notion you put forth is commonly underplayed by conservatives (i'm a conservative to some degree). Some things we sense are in fact extraneous to pain or happiness. Perhaps somethings are tools to how help us feel better or feel worse or they are tools that we'll use later at some point in the future.

can you give some examples?

Then can we interpreted ‘feel better’ as pleasure and ‘feel worse’ as pain?

i'm not the most articulate person out there but i'll try. Tools that promote positive feelings in people. Tools that promote negative feelings in people. Tools that promote some measure of both.

What you say is very important. Everything humans do, from sex to rarified thoughts, can be reduced (sorry @Bitter Crank) to the pleasure principle. Knowing this is both humbling and deeply moving. Humbling because we realize that, despite any attempt to believe otherwise, we're animals. Deeply moving because knowing it reveals our true selves to us.

However, it's not that simple. Humans, due to our intellectual capacity, have managed to study the pleasure principle and discovered that it's a much more nuanced notion when it comes to humans. Yes, we do feel pleasure when we have food, shelter and a mate (like animals) but one philosopher (John Stuart Mill?) subdivided pleasure into higher (exclusive to humans) and lower (common with animals). This distinction is relevant here as an indication that human pleasure is quite unique when compared to animals.

Another thing to note is that humans have discovered that despite being motivated by the pleasure principle their efforts in satisfying this basic need for pleasure often yields result that negate and oppose it. For instance philosophy is a pleasurable activity for some but philosophy shows us that life isn't as great as it could be - there's much suffering and life is meaningless - and that nullifies the very motivation for philosophy, pleasure seeking and replaces it with despair. It's like a thirsty man being given saline water. Initially it appears as though the thirst is being quenched but the man soon finds out his thirst still bothers him.