Most of us have heard someone complaining, “There’s a lack of critical thinking here.” But what do they usually really mean? If we stop for a moment, perhaps we will realize that it often means, “I disagree with your conclusion.” But does that mean that the thought processes used were inadequate?

On the way into work recently, I was listening to the BBC News Hour. The topic was the collapse (failure) of the crypto-currency exchange company FTX. One of the guests brought up the term “consequentialism.” The host did not follow up on that thought, but I made a point to remember it until I could get to a safe spot to look it up.

Last time we introduced a way to look at the factors that cause damage in engineered components and structures.

Twenty-some years ago, when the ASM International Failure Analysis Committee was asked to lead the charge to create a new version of Volume 11 on Failure Analysis and Prevention for the ASM Metals Handbook, I had the chance to work with several colleagues to create the section on the failure-analysis process. 

Before we move on, let’s be clear: Doubt being the essence of critical thinking does not mean paralysis. At some point the thinker makes a choice to move forward. 

A related topic is critical thinking. Over the years, I have come to define critical thinking as the ability to confirm that the proper context has been defined. In more technical language, critical thinking is the process of selecting the most appropriate and useful boundary conditions.

In engineering school, we have laboratory classes so that we can also learn from our own experience. Is the iron crystal structure really cubic? We might be given a chance to perform X-ray diffraction in a lab and be required to work out the angles between the planes of the crystal from the dot patterns on an X-ray detector.

Finally, the technician may examine the fracture surfaces to determine the “% shear.” Shear technically implies ductility at both macro and micro scales, although the test method does not require anything more than a visual check using the eyeballs.

One of most important technical issues that a fracture analyst must deal with is evaluating whether the crack was ductile or brittle. Here we are talking about visible characteristics revealed to the human eye, and we are strictly discussing structures with features that are readily viewed with the human eye.

When I teach people how to do visual examinations as part of the original stage of a failure investigation, I remind them of a very basic group of things that are truly facts.