Does mankind evolve or devolve spiritually? Some philosophers have the idea that humanity is undergoing a spiritual evolution. The most famous representative of this idea is G. W. F. Hegel (whose ideas Marx used and later Communism tried to put into practice). There are also many, more esoteric and religious thinkers, with ideas like that. Rudolf Steiner is one of them; he thinks humanity is evolving spiritually. The common idea between them is that we are in a better position to become acquainted with ourselves as spirit (this idea does not pertain to Marx’ materialist view, though).  

One of my teachers, a Plato researcher, said: “we understand Plato better than Plato could understand himself”? How is this in Buddhism? Is mankind now, 2500 years after the historical Buddha, in a better position to make use of the Dharma? Are we better “equipped for enlightenment”? Is the understanding and insights growing as time goes by? 

Or perhaps it is the other way around? Maybe the distance in time since the start of the spreading of the Dharma makes it more and more difficult for us? Could talk about a spiritual devolution? 

Or is it not changing at all, neither spiritual evolution nor devolution of mankind?
According to Mahayana Buddhism there are Three Ages of Buddhism:

The Former Day of the Law, also known as the Age of the Right Dharma, which lasts between 500-1000 years during which the Buddha's disciples are able to uphold the Buddha's teachings.
The Middle Day of the Law, also known as the Age of Semblance Dharma, (second 1,000 years) during which the teaching only resembles the right Dharma.
The Latter Day of the Law, during which the Dharma declines.

So, according to this, there is devolution in the sense that the Dharma declines over time until it disappears and then the true Dharma will only be re-established by the next Buddha.