The consequence is that physically man is much less specialized than many other animals.
In other words, he is bodily less advanced in the race for competitive extermination.

He belongs to an antiquated, inefficient type of mammal.
His organism is still of the jack-of-all-trades pattern, such as prevailed generally in the more youthful stages of organic life--one not specially suited to any particular pursuit.

Were it not for his cerebral convolutions he could not compete for an instant in the struggle for existence, and even the monkey would reign in his stead.

But brain is more effective than biceps, and a being who can kill his opponent farther off than he can see him evidently needs no great excellence of body to survive his foe.
The field of competition has thus been transferred from matter to mind, but the fight has lost none of its keenness in consequence.

With the same zeal with which advantageous anatomical variations were seized upon and perpetuated, psychical ones are now grasped and rendered hereditary.
Now if opposites were to fancy and wed one another, such fortunate improvements would soon be lost.