If plants don't feel pain because they are not inteligent than what about smart people? Do they suffer more?

I’m not sure you are making a bad assumption here. Plants have been shown to have the ability to sense their surroundings and react to it which might indicate intelligence.

http://www.bbc.com/earth/story/20170109-plants-can-see-hear-and-smell-and-respond

https://www.pri.org/stories/2014-01-09/new-research-plant-intelligence-may-forever-change-how-you-think-about-plants

Plants don’t have brains, but then, apparently, neither to many of the people we consider smart. Well, at least they don’t have common sense.

Common sense is overrated. Everyone believes they have it and believes that almost nobody else does.

It’s not about intelligence, it’s about a lack of a central nervous system. At this point, having a central nervous system is the only way we can understand how organisms experience pain, and since plants lack it, we have no idea how they could even experience pain. That might change though.

What @tinyfaery said.

There is no comparison. Plants don’t have brains or nervous systems.

They may not feel pain, but they can certainly sense danger, at least some can, and they react to it.

All a CNS does is transmit messages. It is not far reaching to believe there are other ways for body parts to communicate.

How would a Venus flytrap know when to snap shut?

Not everyone feels pain the same way regardless of intelligence.
The difference is the level of pain one feels.
Each person has a different threshold of pain that is not based on intelligence or lack of it.

Well the OP was comparing plants and people. Not people and people.
He has the coolest questions.

One truism says “ignorance is bliss”.

But we don’t know (and/or don’t agree) whether plants “feel pain” or not, or how that corresponds to plants.

But the “logic” of your suggestion seems to severely flawed on top of that, and I’d say clearly “no”, intelligence is not proportional to pain, although suffering through awareness of all the stupidity and folly may be increased.

@Zaku Completely agree.

@tinyfaery Plants don’t have a central nervous system and they don’t have brains as we know them. But they do sense things. @Patty_Melt had the perfect example: How does a venus fly-trap know to close when an insect gets in the right spot? They have to feel or sense something to be able to do that. Also, I learned a long time ago that when you are putting in a drain line around your house, wrap some copper wire on the joints. The plant roots will touch the copper and move away. Again, they have to be able to sense something.

The plant is lacking a sense of self awareness, it isn’t about intelligence. The will to live, that sort of thing. Although, plants seem to want to live, but it’s just reflex.

You can break off parts of the plant that aren’t doing well, and the plant seems to thrive even better. It’s different than how animals thrive and survive.

The question isn’t about having the capacity to analyze pain, but about feeling it.

I think that the only way intellectual levels would affect degree of pain would be in understanding the long term damage, and whether death is imminent.

Well, set your hand on fire and rate the pain 1–10. The fact that you ask this question, I’m guessing your pain will be around a 5. If you actually set yourself on fire, then you should be void of pain. So congratulations!

In other words, no. We have pain receptors which plants do not have. This is the reason they don’t feel pain. By “intelligent life”, it doesn’t refer to intelligence involving things like an IQ.