Testing is inherently about looking because, put simply: If you don't look, you're not likely to find. The interesting challenge is to look in the right way at the right place at the right time. This is what motivates any kind of intentional testing: how can we put ourselves in a strong position to look for, see, and — crucially — recognise the things that matter to the people that matter, when they matter? --00-- Tools can help with this mission: using tools we can look more deeply, more broadly, for more complex patterns, for harder-to-spot traces, faster, more often, more efficiently, and so on. There's a trade-off, naturally. As the tool takes us further from the material being worked on we must either trust it more or check its results more thoroughly ... to the extent that we care about the results. At a crude level, think of it as a spectrum. At one end we might have a knife. It's a tool I can use ...