You’ve probably never heard of David Brewster, but you’re likely familiar with his most famous invention: the kaleidoscope. Sadly, I no longer have my childhood kaleidoscope to share a picture of here, but the video segment on how high-quality kaleidoscopes are made, at the end of this post, is probably more interesting than a picture of the cheesy toy I grew up with anyway. However, despite the phenomenal success of his invention as a toy, this Portraits series deals with scientists, not toymakers. Called “The father of modern experimental optics”, and a Fellow of the Royal Society, Brewster certainly qualifies. And yet… he was also a Christian! If you’ve always heard that science and Christianity are mortal enemies, then keep reading. And maybe check out the other scientists in this growing “Portraits” series.
Sir David Brewster was born in Scotland in 1781 and lived until 1868. His parents recognized him as a prodigious learner after he built a telescope at the age of 10, and they enrolled him in the University of Edinburgh at the age of 12 to study for the ministry. But although he did preach after graduating and being ordained as a minister in the Established Church of Scotland, his severe nervousness before crowds led to him pursuing his true calling: in the lab. Brewster contributed much to our knowledge of the polarization of light. In fact, lasers and polarized light microscopes both take advantage of the Brewster angle, the critical angle at which light reflecting off a transparent medium is 100% polarized (it’s 90° to the refracted ray if anyone reading is remotely interested). He also invented the lenticular stereoscope and a binocular camera. He was a contributor to the Encyclopedia Britannica on many scientific articles, as well as editor of the 18-volume Edinburgh Encyclopedia. Brewster worked hard to popularize science and in 1831 helped found the British Association for the Advancement of Science to help promote scientific networking and growth in Great Britain. Another way I was familiar with his work prior to research for this post (besides my toy kaleidoscope) was my exposure in college to something he discovered: the photoelastic effect. This is a pretty neat phenomenon where the stress in certain materials changes the way light refracts through them, resulting in different colors in areas of different shear stresses. This was used in my engineering classes in college to clearly demonstrate the effects of stress concentrations, and in fact, was just used at a seminar I attended recently for that same purpose. He also invented the polyzonal lens for lighthouses in 1811 (commonly called a Fresnel lens after the French engineer/physicist who first outfitted a lighthouse with a similar design in 1822).
So Brewster was a scientist, but was he really a Christian? Brewster wrote the following to a friend in 1828:
Your education and the example you have had to copy will, I am sure, guard you against those presumptuous and sceptical opinions which scientific knowledge too often engenders. In the
ardour of pursuit and under the intoxication of success scientific men are apt to forget that they are the instrument by which Providence is gradually revealing the wonders of creation, and that they ought to exercise their functions with the same humility as those who are engaged in unfolding the mysteries of His revealed will.
Again, to that same friend:
“You will find that a life of science has in it no superiority to any other, unless it is pursued from a higher principle than the mere ambition of notoriety, and that demagogue or a philosopher differ only in the objects of their selfishness. As you will now have experienced how unsatisfying even the pursuit of knowledge is when insulated from higher objects, I hope, if you have not been fortunate enough to begin the study earlier, that you will devote yourself to the most extraordinary of all subjects, one which infinitely surpasses the mechanism of the heavens or the chemistry of the material world, the revelation of your duty and the destiny of man as contained in The Bible — a book which occupied the best hours of the manhood of Newton, of Locke, and of Euler.”
The Scottish botanist John Hutton Balfour recounted to Brewster’s daughter after his death the following:
We were glad to have Sir David Brewster at the Dundee meeting of the British Association, as a noble advocate of Bible truth in opposition to the scepticism of the men of science of the present day. To see a philosopher like him, of world-wide
reputation, vindicating the inspiration of God’s word, and humbly receiving the truth in the love of it, was most encouraging…”
And of course, his last words, as quoted by his daughter:
Jesus will take me safe trough… I shall see Jesus, who created all things, Jesus, who made the worlds; I shall see Him as He is;… Yes; I have had the Light for many years, and Oh! how bright it is! I feel SO SAFE, SO SATISFIED. (emphasis in original)
His daughter recorded much, much more of his steadfast faith in her biography of him – too much to even pick and choose from here. But let me close with a brief summary of that life story. Brewster never saw legitimate science as conflicting with the revealed truth of the Bible. He was a brilliant scientist who was also staunchly opposed to the growing skepticism of his day. And he believed not only that his science was part of his service to God, but also that science was something that could lead men to God. The creation reveals the Creator, for “all truth is God’s truth” (St. Augustine). Sir David Brewster understood that well. Do you?
And for those inquiring minds, below is a segment from “How It’s Made” on the making of a kaleidoscope. Enjoy!
 Margaret Maria Gordon, The Home Life of Sir David Brewster, 1870, pp. 56-58.
 A. D. Orange, “The Origins of the British Association for the Advancement of Science.” The British Journal for the History of Science, vol. 6, no. 2, 1972, pp. 152–176. www.jstor.org/stable/4025289. This Association for advancing science (still operating, by the way) was founded by the Reverend William Vernon Harcourt, a clergyman scientist (much like Copernicus) and, like Brewster, a Fellow of the Royal Society.
 Letter to James David Forbes, dated December 19, 1828, as found in Life and letters of James David Forbes, p. 42.
 ibid, p. 60. Letter dated February 11, 1830.
 Gordon, Home life, p. 387.
 ibid, p.