As an adviser to medical-research foundations on effective donation (see C. Fiennes Nature 546, 187; 2017), I contend that philanthropic capital has an intrinsic advantage over public funding: it thrives on risk. This encourages the testing of bold ideas, even when there's a high chance they might not work out.

Philanthropic capital can withstand failed research outcomes more readily than can public or commercial capital because it is not subject to government processes or shareholders' expectations. It can be swiftly channelled into cutting-edge research that is high risk and high reward. Although the conventional success rate may be lower, the fruitful hits are home runs. And even when fundees fail to fulfil their objectives, a clear answer can count as a hit in itself.

Ideas that test positive open the door to government and commercial capital. In the mid-1990s, for instance, Mike Milken gave a small, unrestricted grant through the Prostate Cancer Foundation to James Allison to explore the promising, yet under-appreciated, field of cancer immunotherapy. Allison went on to win government and commercial funding to realize that promise and bring lifesaving treatments to market.

As well as the “science of philanthropy” that Fiennes calls for, we need to ask how philanthropic funding can catalyse change beyond that achievable through conventional funding sources.