Hiking blisters are from friction.
When things shift, your sock is more likely to stay with your boot than your foot as the two fabrics (or leather and fabric) will catch each other.
This leaves the sock moving against your foot, which causes friction.
When you wear two socks, specifically a smooth liner and a wool hiking sock, the outer sock moves against the inner sock instead of against your foot and less friction is created.
Less friction = fewer blisters.
For the same reason, two pairs of wool won't work as well as what you currently do because the wool is likely to bind and behave like one sock instead of two
outdoors.stackexchange.com/users/236/Stereotypical
There are a lot of unspecified variables involved here... type of socks, fit of the shoe/boot, type of shoe, conditions you are hiking in, etc.
But in general, double-socking may offer the following which may help prevent blisters:
reduced friction - assuming one sock is a thin slick liner sock which tends to stick to your foot while the outer sock sticks to the boot thus keeping the rubbing happening between the two.
moisture control - a liner sock can help wick moisture away from your foot.
Dry feet are happy feet.
additional padding - can prevent hot-spots and pressure points (or can create them, depending on the fit of the shoe) can help take up space - shoes that fit too big can rub more leech control - two pairs of tight woven socks have served me well for 2 years in the tropics warmth - adds additional insulation (though if your boot is a tight fit, this can actually work against you as you decrease circulation/air space...)
If the question is whether double-socking is better , that is unanswerable and totally a question of personal preference.
If 2 socks work for you, and reduce blisters, go for it.
For other people's feet / shoes, 1 sock may be better.
I've even worn 3 socks when my shoes were big enough, and I have hiked with people who wore no socks without issue...
If the question is whether two socks are proven to reduce friction - even that depends on the fabric of the socks, the material and fit of the boot, the foot, and the environment (hot, cold, wet, dry, etc...).
outdoors.stackexchange.com/users/86/Lost
FWIW Ten years ago everyone in the Canadian Forces were issued wool socks.
Now they are all issued two-pair sock systems.
Personally I never once got blisters with wool socks
but I always kept my boots tight.
outdoors.stackexchange.com/users/231/furtive
Two pairs of socks reduces friction and absorbs more moisture, both of which help prevent blisters.
Personally, I prefer thin neoprene socks underneath thick wool socks.
outdoors.stackexchange.com/users/30/Justin C
The esoteric "answer": Try footwraps . Advantages: dirt cheep can be wrapped in any preferrable way, to provide the most padding against the most aggressive edges of Your shoe at a short break(5min) - re-wrap the footwrap in the opposite direction i.e. the cloth,
that is wet from the sweating feet goes up against the ankle and calf to dry out and vice versa at lunch break(30min)
- put the footwraps in the sun and wind.
A footwrap has a lot more surface area than a sock! at night - let the footwraps aerate - they will be fine for another day, due to abovementioned property a (clean) rectangular piece of cloth could have much alternative uses than a ... pair of socks
Disadvantages: can take up to 1 minute to put them on
I have heard of only cotton as materilal.
If you can afford proper technologically-advanced socks, I would expect foot wraps to be inferior (provided breathable boots are used).
stolen from Wikipedia
outdoors.stackexchange.com/users/537/Vorac
I wear two socks every day.
In fact they're just cheap cotton socks that I buy from Walmart.
Although my friends think I'm ridiculous for doing this, it does decrease friction, it aborbs sweat, my feet blister much less, less callouses, more cushion, less stink.
My friends even challenged me to go back to one pair of socks for a while, but it bothers me too much, so after trying it, I never went back to single socks again.
Again, this is just experience with cheap cotton socks.
outdoors.stackexchange.com/users/14792/Jason Henke
From personal experience I tend to wear two pairs of socks, normally some running socks and then my hiking socks on top of that. It helps me avoid blisters. Quite a few of my friends thinks this is nonsense. But with well worn-in boots I always tend to get more blisters if I wear only one pair. Does anyone know if there is any  scientific reason  for this? or is it just an old wives tale?
Is it better to wear one pair or two pairs of socks while hiking?
outdoors.stackexchange.com
<hiking><clothing><boots><socks>
outdoors.stackexchange.com/questions/1013
outdoors.stackexchange.com/users/122/Aim Kai
Some people claim that two pairs of socks reduces friction and absorbs more moisture, both of which help prevent blisters.  Although some may disagree, it can decrease friction, absorb sweat, blister much less, cause fewer callouses,  cushion more and smell less. When you wear a smooth liner and a wool hiking sock, the outer sock moves against the inner sock instead of against your foot and less friction is created.  Wearing two pairs of socks reduces friction and absorbs moisture.
Wearing two pairs of socks reduces friction and absorbs moisture.