Ever assumed you knew something that turned out to be completely different? I know I have. It doesn’t take long to learn how embarrassing hasty assumptions can be. Yet we still have to make a lot of assumptions in life every day. I have to assume when I go to bed each night that my truck will start in the morning, and I don’t actually need to get up at 2 in the morning and run an ultra-marathon just to get to work on time. A dead truck is a possibility, but practically speaking, my assumption of reliable transportation is a fairly safe assumption given that truck’s history of dependability. In engineering, we have to make a lot of assumptions that can drastically change the results, and we’re expected to be able to judge whether those assumptions are justified or not. Assuming certain vibrational characteristics for a project, only to find out your structure’s resonant frequency actually matches the frequency of the average person’s walking gait, can change a client’s bold, cantilevered office building with a view into a nauseating life of trying to do office work on the end of a diving board. Assuming a connection to be rigid when it’s not, or assuming a high frictional resistance that may or may not be present can completely alter load paths, and divert force into components never designed for it. Assuming a beam is adequately braced when it’s not can change the mode of failure from a nice slow yielding to a sudden lateral-torsional buckling, drastically lowering the safe load on the beam, and possibly resulting in a structural failure. Just like assuming a snake isn’t poisonous, a lot of engineering assumptions can pack a deadly bite.

So what is it about assumptions that can be so disastrous? The issue is how close they are to, or how far they are from, reality. In essence, it’s a matter of how truthful the assumption is, for truth is simply correspondence to reality. If I assume the max unbraced length of a 30 foot long beam is 5 feet and it turns out to be 6 feet, then I’m fairly close to the truth of the matter , and I’ve erred on the side of caution, so my design should do well. If I assume it’s 30′ and I don’t need any bracing at all, then I’m working off a false premise, and I’m flirting with disaster. Sadly, a lot of people are making an even more dangerous assumption every day, many never realizing it until it’s too late.

What is this deadly assumption, you ask? Let’s work through some examples of it and find a common denominator:

• “God is love, so that means everybody goes to heaven, right?” This assumes a very one-dimensional caricature of God, who is also just and righteous and holy. One could just as easily state, “God is just and we’re all sinners, so that means everybody goes to hell, right?” Or we could see Him as He has revealed Himself to us, and recognize that His love provided a way for us to be reconciled and justified before His perfect unbending justice, but only if we don’t reject it. Thus, some will be saved and some won’t.
• “I’m a pretty good person, so God surely wouldn’t send me to hell.” This assumes that an absolutely perfect and holy God grades on a curve. We may lower our standards but why assume a perfectly just God would do the same?
• “I don’t need God to be a good person, and that’s what counts, right? – Leaving the world a little better place than I found it?” This common misconception is based on a relativistic notion of “goodness”. But unless you happen to be the one perfect person in the whole world, good isn’t good enough to meet God’s perfect standard. And besides that, a lot of people throughout history have convinced themselves their heinous actions were actually for the “greater good.” So beware of subjective standards of “goodness”.
• “I don’t like this God yours, so I’m going to just find one I like better.” My preference often has little to do with reality, and this dangerous assumption makes the mistake of thinking one’s dislike and rejection of God somehow circumvents the need to deal with God’s independent existence (and our potential obligations to Him) on His sovereign terms.
• “I hadn’t really thought about what happens when I die, but I’m sure it’ll all work out in the end.” When has apathy and sticking one’s head in the sand ever been a good strategy for anything? The person saying this isn’t really sure of anything other than that they don’t want to think about anything that might require them to change course.

There’s a common assumption at the base of all of these statements – that we, as individuals with our finite comprehension, somehow know better than our omniscient Creator how He should’ve done things. It’s the notion that our way – our personal and very subjective way – is the right way, instead of God’s way. Ultimately, it comes back to pride, which, as the Bible wisely warns, “goes before destruction” [Prov 16:18]. So be wise and learn from the mistakes of others, and avoid the eternal consequences of these most dangerous assumptions.