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What I always puzzled over was the following: if our main goal in life is, in fact, to survive/live (and insure the existence of our species through procreation

What I always puzzled over was the following: if our main goal in life is, in fact, to survive/live (and insure the existence of our species through procreation), why would our body, in the case of an allergenic reaction, mount a defense mechanism that could kill us? If your body swelled up to the extent of restricting your ability to breath, why wouldn't your body recognize this as a threat to your existence and counteract the measure? Even if your system made a mistake reacting to the allergen, wouldn't the act of killing itself (your body) trigger another prioritized reaction to take measures to save itself?

JoshTriplett 12y ago
Why would the body include congenital defects of any kind? Bugs and duplication errors that didn't produce useful results. One mutation or genetic development might lead your body to be predisposed to overreact to otherwise harmless allergens; a similar mutation might ramp up your immune system so that you're less vulnerable to fatal diseases. Don't anthropomorphize evolution; it has no intent, and does not actively "select" beneficial traits. Over time, whatever traits happened to propagate will propagate. Some of those will be beneficial; others just didn't happen to kill people. Notice that there's no widespread anaphylactic-level allergy to, for instance, water, or some standard component of atmosphere. But an allergy to peanuts does not systematically kill everyone who has it before they can reproduce.
- rottyguy 12y ago
  I'm not referring to evolution or defects here unless you're implying that it is a defect that our body would willingly choke itself to death in reaction to an allergen (I agree that it's probably a defect that we react to the allergen in the first place)
  - kolinko 12y ago
    Exactly that. Your body has a defect that causes it to choke itself to death in certain circumstances. And thanks to the evolution, if not for science, the defect might be eliminated in a few generations. Or not - perhaps this is an optimal variant of immune the immune system. That is - 90% of organisms will have an excellent immunity, but it will go haywire in 10% of cases, whereas an alternative would be a system with 99% organisms having just an average immune system, but 1% being haywired. Finally, evolution has no "target" or "goal" really. Some features will be broken, and some will be useless. Some may serve a purpose that's beyond our understanding or extremely complex.
mirkoadari 12y ago
If you look at it from the perspective of the entire species instead of an individual, it makes sense. Reproduce with the strongest genes possible. So if the body sees that this particular individual doesn't handle certain substances well, it terminates the line and avoids spreading that particular weakness in the species.
- rottyguy 12y ago
  This sort of makes sense but now we're supposing that the individual, subconsciously, puts it's species ahead of itself. Is this the wide belief or is it that each person fights to keep themselves alive (again, subconsciously, as I believe some people will consciously sacrifice themselves for the greater good).
  - baddox 12y ago
    > This sort of makes sense but now we're supposing that the individual, subconsciously, puts it's species ahead of itself. Not at all. The individuals (and the genes) don't need to have any goals or any notion of autonomy. It could just be that genes come about randomly, and the ones that are most successful at existing in the future will be the ones that cause a small portion of individuals to die when doing so increases the odds of survival of the rest of the individuals.
dragonwriter 12y ago
> if our main goal in life is, in fact, to survive/live (and insure the existence of our species through procreation), why would our body, in the case of an allergenic reaction, mount a defense mechanism that could kill us? Because our bodies are the product of selection over random variation, not perfectly crafted designs for survival. So we end up with systems that, while some are surprisingly simple and elegant, are often complex, convoluted, and despite working well and correctly most of the time in normal cases (and even often in many extreme ones) still can have very bad failure modes.
- rottyguy 12y ago
  We have so many built-in mechanism designed to keep us alive that I find it strange a counter measure to extreme inflammation would be excluded. Pain sensors, fear, adrenaline, etc.
  - saraid216 12y ago
    Inflammation is itself a countermeasure. It's the same principle as boiling water before you drink it or cooking meat before you eat it. How many countermeasures do you provide for the countermeasures?
ArkyBeagle 12y ago
Evolution isn't intentional. That which does not kill you gets passed on to the next generation. "Your body" doesn't have anything like the ability to analyze good or bad. Some mysterious emergent phenomena in your brain does, but the overall mechanisms we reused from other species don't.
baddox 12y ago
Perhaps "what doesn't kill you only makes you stronger" applies here. The mechanisms that kill some small percentage of people might increase the survivability of the vast majority of people.
deeviant 12y ago
It's a question of risk vs reward. Your body has an extremely complicated and mostly successful system of defence. If a pathogen enters the body and is not attacked, it may easily kill you, for this reason pathogens, once identified, are always attacked. There is a system that is responsible for identifying threats(lymphocyte), some times this messes up and identifies the wrong thing as a threat. This is easier than you might think because your body makes antibodies(attack living stuff like bacteria but quasi stuff like viruses) and antitoxins(attacks toxins), when the body sees a foreign substance in the blood, it only takes one lymphocyte is misread it as a threat, and boom all-of-sudden your body fights like the devil to kill/remove/subdue that thing. Backing down the response would alleviate some allergy problems, but it would also cause the body to perhaps miss some actually-bad things in your system. It'll be hard to change this, and problem inadvisable, as the system has been tuned over millions of years. The best course of action is probably treating symptoms, or finding targeted and intelligent ways to trick the system into handling these corner cases better.
- rottyguy 12y ago
  Let's say someone punches you in the nose and breaks it. It'll hurt. You'll bleed out a bit, eyes water, and you're throbbing pain. Let's further say that someone then proceeds to choke you with their bare hands. Your immediate instinct, even though your nose is in a world of hurt, would be to try to escape because breathing is prioritized higher than a bloody, throbbing nose. While I am no pathogen expert, I can't imagine many things (if anything) more dire to the human body then oxygen deprivation. To the extent that if you're intentionally holding your breath, you'll pass out and your body will involuntarily start breathing again to keep you alive. That said, maybe the body does view internal (pathogen/poisons) attacks more critical to preserving life then oxygen. Anyone know?
InclinedPlane 12y ago
One could ask the same of obesity. The simple answer is that the conditions of life we face day to day now are different from those to which our bodies evolved for.

JoshTriplett 12y ago

Why would the body include congenital defects of any kind? Bugs and duplication errors that didn't produce useful results. One mutation or genetic development might lead your body to be predisposed to overreact to otherwise harmless allergens; a similar mutation might ramp up your immune system so that you're less vulnerable to fatal diseases. Don't anthropomorphize evolution; it has no intent, and does not actively "select" beneficial traits. Over time, whatever traits happened to propagate will propagate. Some of those will be beneficial; others just didn't happen to kill people. Notice that there's no widespread anaphylactic-level allergy to, for instance, water, or some standard component of atmosphere. But an allergy to peanuts does not systematically kill everyone who has it before they can reproduce.

rottyguy 12y ago
I'm not referring to evolution or defects here unless you're implying that it is a defect that our body would willingly choke itself to death in reaction to an allergen (I agree that it's probably a defect that we react to the allergen in the first place)
- kolinko 12y ago
  Exactly that. Your body has a defect that causes it to choke itself to death in certain circumstances. And thanks to the evolution, if not for science, the defect might be eliminated in a few generations. Or not - perhaps this is an optimal variant of immune the immune system. That is - 90% of organisms will have an excellent immunity, but it will go haywire in 10% of cases, whereas an alternative would be a system with 99% organisms having just an average immune system, but 1% being haywired. Finally, evolution has no "target" or "goal" really. Some features will be broken, and some will be useless. Some may serve a purpose that's beyond our understanding or extremely complex.

mirkoadari 12y ago

If you look at it from the perspective of the entire species instead of an individual, it makes sense. Reproduce with the strongest genes possible. So if the body sees that this particular individual doesn't handle certain substances well, it terminates the line and avoids spreading that particular weakness in the species.

rottyguy 12y ago
This sort of makes sense but now we're supposing that the individual, subconsciously, puts it's species ahead of itself. Is this the wide belief or is it that each person fights to keep themselves alive (again, subconsciously, as I believe some people will consciously sacrifice themselves for the greater good).
- baddox 12y ago
  > This sort of makes sense but now we're supposing that the individual, subconsciously, puts it's species ahead of itself. Not at all. The individuals (and the genes) don't need to have any goals or any notion of autonomy. It could just be that genes come about randomly, and the ones that are most successful at existing in the future will be the ones that cause a small portion of individuals to die when doing so increases the odds of survival of the rest of the individuals.

dragonwriter 12y ago

> if our main goal in life is, in fact, to survive/live (and insure the existence of our species through procreation), why would our body, in the case of an allergenic reaction, mount a defense mechanism that could kill us? Because our bodies are the product of selection over random variation, not perfectly crafted designs for survival. So we end up with systems that, while some are surprisingly simple and elegant, are often complex, convoluted, and despite working well and correctly most of the time in normal cases (and even often in many extreme ones) still can have very bad failure modes.

rottyguy 12y ago
We have so many built-in mechanism designed to keep us alive that I find it strange a counter measure to extreme inflammation would be excluded. Pain sensors, fear, adrenaline, etc.
- saraid216 12y ago
  Inflammation is itself a countermeasure. It's the same principle as boiling water before you drink it or cooking meat before you eat it. How many countermeasures do you provide for the countermeasures?

ArkyBeagle 12y ago

Evolution isn't intentional. That which does not kill you gets passed on to the next generation. "Your body" doesn't have anything like the ability to analyze good or bad. Some mysterious emergent phenomena in your brain does, but the overall mechanisms we reused from other species don't.

baddox 12y ago

Perhaps "what doesn't kill you only makes you stronger" applies here. The mechanisms that kill some small percentage of people might increase the survivability of the vast majority of people.

deeviant 12y ago

It's a question of risk vs reward. Your body has an extremely complicated and mostly successful system of defence. If a pathogen enters the body and is not attacked, it may easily kill you, for this reason pathogens, once identified, are always attacked. There is a system that is responsible for identifying threats(lymphocyte), some times this messes up and identifies the wrong thing as a threat. This is easier than you might think because your body makes antibodies(attack living stuff like bacteria but quasi stuff like viruses) and antitoxins(attacks toxins), when the body sees a foreign substance in the blood, it only takes one lymphocyte is misread it as a threat, and boom all-of-sudden your body fights like the devil to kill/remove/subdue that thing. Backing down the response would alleviate some allergy problems, but it would also cause the body to perhaps miss some actually-bad things in your system. It'll be hard to change this, and problem inadvisable, as the system has been tuned over millions of years. The best course of action is probably treating symptoms, or finding targeted and intelligent ways to trick the system into handling these corner cases better.

rottyguy 12y ago
Let's say someone punches you in the nose and breaks it. It'll hurt. You'll bleed out a bit, eyes water, and you're throbbing pain. Let's further say that someone then proceeds to choke you with their bare hands. Your immediate instinct, even though your nose is in a world of hurt, would be to try to escape because breathing is prioritized higher than a bloody, throbbing nose. While I am no pathogen expert, I can't imagine many things (if anything) more dire to the human body then oxygen deprivation. To the extent that if you're intentionally holding your breath, you'll pass out and your body will involuntarily start breathing again to keep you alive. That said, maybe the body does view internal (pathogen/poisons) attacks more critical to preserving life then oxygen. Anyone know?

InclinedPlane 12y ago

One could ask the same of obesity. The simple answer is that the conditions of life we face day to day now are different from those to which our bodies evolved for.