The interesting thing to me is the argument that the ad was confronting. That is that cigarettes are harmful one way or the other - which despite there being at the time almost zero evidence for apparently enough people thought that there was a need to cloak a particular brand with the association to doctors (who would presumably be smoking the "healthiest" cigarette).
More generally I'm all for evidence showing what's healthy - eat some fruit and vegetables occasionally, get some exercise, don't smoke, don't drink - but I don't think any of these things are mysterious. Generally people have a good handle on what's good and what's bad for them. Now, they don't always do it but that's less to do with evidence then people seem to commonly suppose.
> despite there being at the time almost zero evidence for
This isn't true—people had been connecting the dots for a few decades by the time these ads were running [0], and right around the start of the run (1940) was when strong evidence was starting to get published:
> Scholars started noting the parallel rise in cigarette consumption and lung cancer, and by the 1930s had begun to investigate this relationship using the methods of case-control epidemiology. Franz Hermann Müller at Cologne Hospital in 1939 published the first such study, comparing 86 lung cancer ‘cases’ and a similar number of cancer-free controls. Müller was able to show that people with lung cancer were far more likely than non-cancer controls to have smoked, a fact confirmed by Eberhard Schairer and Eric Schöniger at the University of Jena in an even more ambitious study from 1943. These German results were subsequently verified and amplified by UK and American scholars: in 1950 alone, five separate epidemiological studies were published, including papers by Ernst Wynder and Evarts Graham in the USA and Richard Doll and A Bradford Hill in England. All confirmed this growing suspicion, that smokers of cigarettes were far more likely to contract lung cancer than non-smokers.
So it's less a case of people intuiting what was bad for them and more a case of the industry trying (and for a few decades succeeding) to get ahead of a growing scientific consensus by advertising it into irrelevance.
Point of Order: tobacco smoke was suspected of being harmful a couple centuries before the scientific method started to catch up to the suspicion. King James I famously penned a treatise against tobacco use in 1604 and slapped some eyewatering taxes on it's importation.
That's true—lung cancer specifically was a concern that was growing at the time, which is almost certainly the impetus for this ad campaign—but you're right that it was strongly questioned for a long time before that.
> Generally people have a good handle on what's good and what's bad for them
Hard disagree, the cultural norms play a huge role and the changes are slow. I'm like 95% sure the unabated addiction to social media so prevalent nowadays will be regarded similarly to how smoking and drinking is seen now.
We should be really extrapolating what we know about tobacco now and the things they claimed in the past towards currently relevant issues e.g. "Facebook papers"-type materials.
I don't understand why you think there would have been 0 evidence. The countless respiratory illnesses associated with smoking are readily obvious by taking even a small sample of longterm smokers - a decent chunk of them will sound like smokers, be occasionally hacking up a lung, and so on.
People obviously knew smoking was unhealthy, but chose to do so anyhow. And companies naturally worked to trt to strengthen that cognitive dissonance. Same thing today, but it's slightly more subtle. For instance in a typical Coke ad you'll generally see people that look nothing like regular Coke drinkers - health, fitness, and good body weights abounds.
More generally I'm all for evidence showing what's healthy - eat some fruit and vegetables occasionally, get some exercise, don't smoke, don't drink - but I don't think any of these things are mysterious. Generally people have a good handle on what's good and what's bad for them. Now, they don't always do it but that's less to do with evidence then people seem to commonly suppose.