CrossFit | Modern Science

Modern Science

ByCrossFitFebruary 10, 2020

This series tackles the problem of constructing a formal definition of modern science, developing a definition that meets the needs of practitioners. In our category of “practitioners of modern science,” we include those working in fields wherein a successful outcome is immediately and visibly dependent upon accurate prediction, such as technology and industry. This definition and its implications are also useful, maybe essential, to any individual seeking to understand reality in terms of cause and effect, or to engage thoughtfully with the products of scientific inquiry and practice. It is a definition that provides clarity — and an understanding that cultivates a healthy skepticism — in the chaotic world of pop science, sensational health headlines, and the creeping dominance of “scientific” fields such as nutritional epidemiology.

In the process of constructing a definition, we analyze our expectations of science. The process begins with an examination of the limits of human perception and knowledge. Our need to break through the bounds of individual perceptions is the same as our need to share knowledge and creates a requirement for objectivity. This leads to both a definition and a mission statement for science, which is the objective branch of knowledge. 

In addition to knowledge and objectivity, key words in the defining process include creativity, discovery, language, logic, mathematics, measurements, models, predictions, and validation. All of these can be structured within the scientific method, as we will explore.

What qualifies as science is that which practices the scientific method. How far an art or a model within an art can go in satisfying the method yields criteria for acceptance or rejection. The same criteria provide quality ratings that everyone can apply unambiguously to the state of development of an art or a scientific model. The resulting subjective model grades through four progressive and familiar stages: conjecture, hypothesis, theory, and law.

Science Defined

We must offer a definition of science in order for it to be rationally taught. Science demands precision in language, and it cannot thrive without it.

  1. Science is a branch of knowledge. Science is not an obscure occupation, safely ignored by anyone who might lack interest in its study or by the intellectually lazy. It is impossible to escape its realities and consequences.
  2. Science is the objective branch of knowledge. Science has no bounds to its domain other than dealing with things that man can define, record, measure, and quantify or order. Even these attributes will not assure objectivity, as even a group of well-trained observers can fool themselves into thinking that the group has made a discovery. From early childhood, each person’s senses and mental models shape their perceptions of the real world. These models are created by the brain and, in spite of their imperfection, are essential for the interpretation of our senses. These models are the essence of both observation and subjectivity, and they can be improved through training in science.
  3. Science is shared, public knowledge. Objectivity, the stripping of the subjective from our mental models, comes from open sharing. Sharing mandates the least ambiguity. Openness allows criticism and growth. Sharing allows others to make similar observations in spite of their subjective biases. It empowers many brains to concentrate coherently on a subject. We can distinguish this from the post-modern science emphasis on consensus, which constructs a paradigm whereby votes or popularity define a result rather than open-source, critical testing.
  4. Science creates models that account for observations of the real world. Science creates objective models that replace private, subjective models. These scientific models account for all relevant facts in their domain and predict new phenomena or relationships.
  5. Scientific models build on measurements of the observations. Measurements, the result of comparing observations with standards, provide consistency in observations and permit the sharing of experiences in an objective way. Measurements create facts; facts are measurements.
  6. Scientific models require validation through demonstrated predictions of qualitatively new phenomena or relationships. A qualitatively new phenomenon is one involving different parameters than those that formed the facts the scientist used to create the model.

Objective knowledge evolves like life, proceeding randomly from a settled base into perpetually new territories. The progress may be guided by the most intelligent humans on Earth, but it is random because success has a large unpredictable component. Strong theories survive, subsuming weak theories or abandoning them to die. Complex ideas build on the simple. The trends are positive, and the process is irreversible.

This series includes revised text from Evolution in Science, 1995, by Jeff Glassman, Ph.D., adapted with permission.

Comments on Modern Science


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Jose Espinosa
June 2nd, 2020 at 6:33 am
Commented on: Modern Science

I am improving my English

is awesome 👏 i really appreciate the information 🙏

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John Smith
February 11th, 2020 at 1:26 pm
Commented on: Modern Science

Notice words that were left out of this article. Words like industry, government, interests, commissioned, grants, and funding. Those are not science. Science is the objective core, but that kernel is surrounded by elements which make up the research enterprise game.

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Greg Glassman
March 4th, 2020 at 8:00 pm

John, I'd include scientific misconduct, consensus, peer review, fraud, tenure, lack of replicability/reproducibility and more to describe what it is that the "kernel" of modern science "is surrounded by" but the word "corrupted" fits better in the academic "research enterprise game" than "surrounded". These corruptions are at the heart of consensus science (postmodern or academic science) and don't just surround it.

I think that it's important to differentiate academic and industrial science in looking at the "research enterprise game" and shortcomings.

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Dany Lafontaine
June 25th, 2020 at 6:39 pm

While I agree with you that at its core the words you listed do not represent science, in reality they are intertwined. Why is that? Because of lack of funding for research and the ridiculous productivity expectations placed upon researchers nowadays. The sheer volume of publications being generated makes little sense and their quality becomes questionable.

Pay to play journals are popping up on a seemingly daily basis. Exercise scientists are becoming more and more "disease scientists" instead of following their true passion. Hardly anyone studies sports or exercise modes because the funding just isn't there. While flawed, the peer review process is still the best option to determine the quality of a scientific paper.

As for integrity of the researchers themselves, it is a self-regulation process with some occasional disruptions. Lack of tenure positions puts researchers on edge and constantly at risk of unemployment. Painting academic research with such a wide and negative brush is an insult to the majority of the devoted and honest academic researchers, and does no service to the point you're trying to bring to the publics' attention.

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Nathan Jenkins
February 11th, 2020 at 2:27 am
Commented on: Modern Science

File this article under "Greg Glassman doing Greg Glassman things."

In the same way that a useful definition of fitness did not exist in the academic literature before Greg presented "work capacity across broad time and modal domains", here we have a definition of science that has more utility than any that I've encountered in my career as an academic (~15 years; now a tenured professor at a major research university, for context).

Not sure that this article will be as widely read and circulated as the original "What is Fitness" article, but it's equally revolutionary in its conceptual advance.

All affiliate owners and CrossFit trainers would do well to familiarize themselves with the distinction between modern and post-modern science. The services you provide to your clients are rooted in modern science. Your critics and detractors are generally coming from a post-modern science perspective.

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Nuno Costa
February 11th, 2020 at 3:15 pm

Loved reading this article - and I also hope this becomes just as popular and standard as Glassmans definition of What is Fitness. Good to see you comment on here - I remember your presentation at our trainee summit and how insightful it was!

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Nathan Jenkins
February 11th, 2020 at 3:46 pm

Thanks Nuno! I try to get on here when I can but there is so much good content that it's tough to keep up!

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Tyler Hass
February 12th, 2020 at 12:58 am


It's nice to hear your take on this article. CrossFit really is a unique place. Where else do you get serious discussion of the fundamentals of science?

The early days of CrossFit were especially fun, when the critics denounced CrossFit entirely on theoretical grounds. Most people then had not experienced CrossFit or seen the results of others, so the refutations were purely hypothetical. They would say in one breath that CrossFit does not fit within their theoretical model and is refuted by their theoretical model.

I really appreciate that you were willing to try CrossFit on yourself before judging it on theoretical grounds. Few in the exercise science community have done that.

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Nathan Jenkins
February 12th, 2020 at 1:29 am

Tyler -

You and the team are doing a phenomenal job putting out some excellent content on the site. Please keep it coming.

I wish I had been around in those early days. I didn't pick up CrossFit until 2015, 5 years ago last month. I'm still a newbie in the grand scheme of things. I'd like to think that had I encountered CrossFit in, say, 2005, I would have had the same open minded approach, rooted in scientific curiosity. I don't know that I would have. By the time I picked up a barbell for anything other than the bench press or curls in the squat rack, the efficacy of CrossFit was already widely known by pretty much everyone except the exercise science community. So I've always had this feeling of playing catch up, learning things that everyone else around me already knew, except for me.

You're spot on about the rejection being on purely theoretical grounds. I am sorry to report from the academic front lines that the situation is actually getting worse, at least in some circles: the rejection continues, on the same purely theoretical grounds.

The difference between 2020 and 2005, and the reason I say the situation is worse, is that now, there are plenty of empirical data, both in the published literature and from the 2 million+ CrossFitters in 15,000+ affiliates around the world, to support CrossFit as perhaps the optimal approach to attaining and maintaining fitness and health. So yes, the rejection is based on theories, except the theories are now categorically rejected, at least when we rigorously apply the scientific method to our reasoning. We have plenty of data to support that.

But I'm learning more and more that scientific data tend to have little impact on beliefs. Apparently, belief systems about fitness are multi-faceted and objectively-measured scientific data tend to have less of an effect on beliefs than I might have expected, even, unfortunately, among people with PhDs who self-identify as scientists.

Hope to make it back out to HQ soon. Keep up the great work. This is important stuff. These articles are helping to mitigate my growing cynicism :)


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Tyler Hass
February 12th, 2020 at 4:48 am

I was fortunate to stumble upon CrossFit in 2001, because I was looking to integrate gymnastics into my kettlebell/sprints/barbell training. There was barely any gymnastics training information online and no one else was discussing it in terms of fitness. My group of friends in Seattle that I trained with were all willing to give CrossFit a shot. This was before CrossFit even had critics, so no theoretical objections got in the way!

We had no idea what we were doing. There were no videos of CrossFit, so we weren't aware that the pullups were done with a kip. But even then, there was an incredible community forming around CrossFit, so we all learned a ton.

Within the exercise science community, you're an early adopter. There seems to be a changing of the guard happening within exercise science, so it will be exciting to see what develops. I know I'm one of many who value your perspective and I hope you can make more trips out to HQ.

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Joe Masley
February 12th, 2020 at 3:16 pm


This article was awesome and I already sent it out to all my coaches to read for our weekly coaches development before reading your comment - for exactly the reasons you put down.

As always, I'm grateful to have your professional insight from the exercise science world here to further validate what CrossFit stands for. You are definitely a pioneer and I hope that more in your field start to follow your lead.

Thanks for being a great part of our community and keep up the awesome work!


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Tom Hunt
February 14th, 2020 at 9:48 am

This is a fantastic article for those of us not in scientific academia, and the comment thread is also equally enlightening. Thanks, all very useful!

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