According to Julian Huxley (arguably one of the most prominent evolutionists of the last century) at least one million positive mutations were required for the modern horse to evolve. He believed that there is a maximum of one positive mutation in a total of 1,000 mutations. With the help of these values Huxley calculated the probability for the horse to have evolved from one single unicellular organism was 1 in 103,000,000. He believed, however, that natural selection would be able to solve this problem. But this faith did not help him in the end, and will not help any other evolutionist either, as this calculation is based on the origin of positive mutations, even before natural selection would start to work. If all electrons in the universe (about 1080) would have participated in 1012 reactions every second, during the 30 billion years which evolutionists have put as the upper age limit of the universe, there would still not have been more than c. 10110 possibly interactions—still a long way from the Huxley calculation.
