It can be easy for an abstract concept – like time – to become lost on people. As we enter the third decade of the 2000s, this can become increasingly disorientating.

How could it already be 20 years ago that we watched the ball drop on a new millennium? How can it be nearly 20 years since our world changed forever in the face of despicable terrorism? How can 100 years have passed since women first earned the right to vote? How can we have gone from the internet being a silly fad to literally running our entire world?

The passage of time offers us an unceasing existential crisis in the fact that we have an always-ticking clock reminding us of our ultimate earthly mortality, but it also provides us a valuable frame of reference for how much progress can actually occur in even just one lifetime.

For example, while it may seem like just yesterday to some that we landed on the Moon, we just celebrated the 50th anniversary of that monumental accomplishment this past summer. It was only about one year prior to that when Martin Luther King Jr. – whom we look to celebrate on Monday – was gunned down in Memphis.

In the 50-plus years since, we’ve progressed from a country in which having a different skin color and speaking out about injustice would leave you in the crosshairs of an assassin’s rifle into a country where an African American was not only elected to be president of the nation but re-elected and remains a popular icon among the populace today – albeit not to everybody.

In the years since the moon landing, our development of electronics and computers has surpassed what even the astronauts that piloted those early space craft would have thought was possible. And for all the negative consequences of this technology, much of which is only recently becoming clearer, it has also done tremendous things for society and made our lives richer, more connected and more empathetic to one another. It has allowed our citizens to learn more, see more, and become more well-rounded people.

In other words, the world we’ve created today is one that Martin Luther King Jr. would have been proud of.

For sure, we haven’t eliminated the blights of tribalism, racism, classism or bigotry that continue to divide us or sew hatred throughout our communities – but we have a much greater resistance to them and a much more informed populace to refute those progress-stymieing elements of our culture. As time moves on and people become more exposed to different cultures, we will continue to see improvements in this area.

Martin Luther King Jr. fought against the tide, protesting societal issues that a majority of the populace either didn’t think were a problem or actively sought to challenge and defeat him on. Today, the societal issues of inequity, racism and institutional oppression still exist in many different forms, but are actively challenged by many activist groups in the areas in which they are found. Speaking out against injustice is no less brave today than it was in Martin Luther King’s time, but you will likely be able to find many more allies – and much quicker – than the late reverend could have dreamed of.

To bring back the abstract concept of time – our perception of it can be wonky. Our brains can make it seem like yesterday that movies like Jurassic Park and Forrest Gump were released in theaters, but the moon landing can feel like a completely bygone era to those who didn’t experience it. In fact, the same amount of time passed between the Moon landing and the release of those movies – a little over 25 years – and the amount of time that has passed between those movies coming out, and today.

The expression “time marches on” is an especially poignant one, especially in reference to Martin Luther King Jr. It is not always the case that, as time continues to march, it leads the society tracking it into a better place. So far, by all-important measures (like quality of life, violent crime rates and life expectancy), life has gotten better since the days of Martin Luther King.

Now it is our duty to steward our society forward through the coming passage of time in a way that will make future generations proud.