Here's a little bit of wisdom for today- Two heads are better than one.
And here's another- there are no two-headed giants in the world. Not anywhere outside of natural history museums, anyway. Two-headedness simply did not provide any evolutionary advantage over one-headedness. What is interesting is that the adage originates from the village of Triskelion, where three-headed ogres reside.
Rather than describing the benefits of cooperating, the original meaning of the saying instead alludes to the unique advantages of three-headedness (and indirectly, why two-headedness does not). For those unfamiliar with three-headed ogres, three-headed ogres are large humanoids with three heads, but otherwise have one body (if oversized) and the same pairs of appendages as any other humanoid. Each head of the ogre sustains an individual mind thinking independently of the other two. The question everyone is asking is, with three heads and one body, what dictates how the body acts?
The answer is somewhat complicated, but it goes like this: Each day, two of the three heads are randomly selected to serve as proposers, where the selected heads would individually propose actions to undertake. The remaining head would act as an arbiter, and would choose which action to adopt at any point of time. In this fashion, the actions of the three-headed ogre evolve from a fused consensus of its three heads.
The advantage of this three-headed decision process is a moderation of excessive or reckless behaviors. Implicitly, any action must be supported by at least two heads. Indeed, two heads prove to be better than one.
What about our now extinct two-headed giants? We might speculate that with only two heads, it would be impossible to resolve disagreement between the two, or that one head would naturally be dominant. Without any surviving members of the species, it is difficult to make any supported conclusions.