Technology is a science. It’s semiconductors and code and batteries.

But Steve Jobs talked about how the iPad was playful and begged you to pick it up as much as he’d talk about its processor. The iPhone is a technological marvel, but Jobs spent a lot of time talking about how it felt in your hand, and the experience of opening the box.

Job’s insight, and the most important factor in Apple’s success, was realizing that technology isn’t merely a science. It’s just as much an art.

A lot of industries work like this. Medicine is a science, but the bedside manner of being a good doctor is an art. Building cars is the science of engineering. Designing cars is the art of curves and lines.

This drives people crazy, because the more important a field is, the more scientific and predictable we want it to be. People take scientists seriously because they can count of them. Art is taken less seriously because it comes and goes.

But most fields outside academia are both science and art.

Including investing.

Investing is maybe 60% science, the rest art. Yes, it has numbers and formulas and rules. But the soft stuff you can’t measure or hardly even describe – the art of the business – makes all the difference in the world.

Building a valuation model is a science. Calibrating it to reflect the psychology of uncertainty is an art.

Gathering information is a science. Filtering out noise is an art.

Net present value is a science. Identifying the trust and passion of a CEO is an art.

Measuring what worked in the past is a science. Understanding why things are different now is an art.

It’s art because you can’t measure it or rely on a repeatable set of rules. Science has formulas. Art has fads. Science has calculations. Art has feelings. Science has laws. Art has eras. Science can be taught. Art has to be experienced. You can spend a lifetime proving the science of why something should or shouldn’t be, only to have the art part of the equation humble you into the ground.

The difference between science and art is basically this: Science often provides multiple ways of getting something done. But if any of those ways contradict each other, then art is playing a role.

There is scientific data showing the best way to invest is to buy the cheapest set of companies you can find. There’s equally persuasive data showing the best way to invest is to buy the fastest-growing set of companies, which tend to be expensive. Some investors obsess over brand and intangibles. Others say ignore those and only look at fundamentals. Neither is right or wrong. You just have to appreciate that each strategy lives in its own context, and that market trends come and go. It’s an art.

Warren Buffett demonstrated this when describing his thesis for investing in Coke. He had numbers in his favor. That was the science. But he also said consumers associate Coke with happiness, which is something you can’t measure. “Forget about share of market. I’m talking about share of mind,” he once told a classroom – a statement that is as important as it is unscientific.

Venture capitalist Chris Sacca echoed something similar when he said “I have never used a spreadsheet in deciding whether to make a seed investment. Not one.” VC is a people business where you’re looking for passion and boldness. Which is a little science and a ton of art.

Coming to terms with investing being both science and art exposes a few things.

There are few experts. Pure science has experts, because there’s precision and laws that will never fail you. But when art is mixed with science, the idea of an “expert” diminishes. No one can fully understand the power of changing moods and shifting expectations, which are hard to even define. Some investors are better at navigating the ups and downs of investing than others, and some can tip the odds of success in your favor. But there are few investing experts in the same way there are, say, expert electricians.

There are many ways to skin a cat. All kinds of investing styles, some of them contradictory, can work. This is partly because investors have different goals, and partly because markets change. I try not to criticize investing styles I don’t understand for the same reason I don’t criticize art I don’t like. It might work for some people.

Skill is hard to identify. If I build a machine that makes widgets, you can clearly identify my engineering skill. But if I make a lot of money from investing, I may have been just been lucky, at the right place at the right time. The soft, art part of investing makes identifying skill really hard. The solution is to appreciate process over outcome, but this is easier said than done. People like the perceived science of being right. The art of being able to repeat it is harder to grasp.