Comment by motorest

>How many experiments, prototyopes, iterations go into building a car or a rocket? Many. Engineers do not come up with the final design up front.

No where did anyone claim you need the full final design up front. For cars\rockets how many of those experiments, prototypes, and iterations had designs? All of them. You never see a mechanical engineer walk out to the shop and just start hammering on a pile of slop until it sort of looks like a car.

>The difference it is that this is expensive while in software we can iterate much more, much quicker, and for free to get to the final product.

If you have no design to meet how do you judge the output of an iteration or know you have arrived at the final product?

> I do not and I have explained it.

You should review the sources of your confusions and personal misconceptions, as you deny design and then proceed to admit there is design.

> And part of my previous comment is that this "waterfall-y" approach in which you design first and implement second does not work and has never worked.

Nonsense. "Big design upfront" works, but is suboptimal in software development. That's why it's not used.

"Big design upfront" approaches are costly as it requires know-how and expertise to pull off, which most teams lack, and it assumes requirements don't change, which is never the case.

Once you acknowledge that requirements will change and new requirements will emerge, you start to think of strategies to accommodate them. In software development, unlike in any hard engineering field, the primary resource consumed is man-hours. This means that, unlike in hard engineering fields, a software development process can go through total rebuilds without jeopardizing their success. Therefore in software development there is less pressure to get every detail right at the start, and thus designs can be reviewed and implementations can be redone with minimal impact.

> Exactly, and not only that but usually requirements will also change along the way. The design can change and will change as you hit reality and learn while writing actual, working code.

Yes.

But you do need a design upfront, before code is written. Design means "know what you need to do". You need to have that in place to create tickets and allocate effort. It makes no sense at all to claim that writing code is the design stage. Only in amateur pet projects this is the case.

> The difference I see is that in other fields, part of your design process is thinking through the logical details of the thing. Essentially, doing some math.

The "some math" is used in engineering fields in things like preliminary design, sizing, verification&validation, etc. To a lesser degree, "some math" can be used in the design stages of software development projects. For example, estimating the impact of micro services tax in total response times to verify if doing synchronous calls can work vs doing polling/messaging. Another example is estimating max throughput per service based on what data features in a response and how infrastructure is scaled. This is the kind of things that you do way before touching code to determine if the expected impact of going with a particular architecture vs another that mitigates issues.

> In software, the logical details are the finished product. The math is what you're trying to make.

You're confused. The design stage precedes writing any code, let alone the finished product. Any remotely complex work, specially if it involves architecture changes, is preceded by a design stage where alternatives are weighed and validated, and tradeoffs are evaluated.

To further drive the point home, in professional settings you also have design reviews for things like security and data protection. Some companies even establish guidelines such as data classification processes and comparative design to facilitate these reviews.

> If you've actually thought through all of the details, you have written the software (if only in your head). If you haven't thought through all of the details and only figured out a high level design, you've still written some software (essentially, stubbing out some functionality, or leaving it as a dependency to be provided. However you want to think of it).

You're confusing having a design stage with having a big design upfront. This is wrong.

The purpose of the design stage is to get the necessary and sufficient aspects right from the start, before resources are invested (and wasted) in producing something that meets requirements. No one cares what classes or indentation style you use to implement something. The ultimate goal is to ensure the thing is possible to deliver, what it actually does and how it does it, and if it is safe enough to use. You start writing code to fill in the details.