One of the most brilliant mathematicians of the late 19th century was the Englishman William Kingdon Clifford. Clifford also dabbled in philosophy and was noted for expounding this principle: "It is wrong always, everywhere and for anyone to believe anything on insufficient evidence."

That is, you should never believe something merely because you think it is true or on the basis of evidence that is anything less than indubitable. Applying Clifford's principle would lead one into a most humourless existence with one ever seeking to find sufficient evidence for the truth of even our most mundane beliefs.

Clifford actually lacked sufficient evidence for the truth of his own principle, but such a lack of evidence did not faze him. He assumed the truth of his principle on faith alone, and used the principle to attack any beliefs founded on religious faith.

While Clifford was a walking contradiction, his principle should be a reminder that faith is not subjective, that it must be founded on truth. The basis for establishing truth, however, is not some ironclad mathematical certainty. The vast majority of the truth claims that we make are far from certain.

However, the possibility that what we believe might be false should not lead to a subjectivism which says, "I have my truth, and you have your truth. Neither of us can impose our truth on the other."

In his encyclical Lumen Fidei (Light of Truth) (LF), Pope Francis maintains that faith must be more than "a lofty sentiment," more than "a beautiful story" (24). There is no salvation in beliefs that make us feel good, but which are not true.

We are saved by truth. Truth enables us to stand firm so we can move forward in life. Over the centuries, numerous people have given their lives for the truth, truth which impelled them to refuse to bow before the power of those who made their own self-interest the ultimate standard.

So how does one know the truth? Trust. "Because God is trustworthy, it is reasonable to have faith in him, to stand fast on his word" (LF 23).

This is an unsurprising answer, one which would nevertheless not satisfy William Kingdon Clifford. As discussed in the second article in this series four weeks ago, virtually all of our knowledge, not based on direct experience, is founded on trust.

The question every person must face, at least implicitly, is what is the most reasonable basis for knowing truth – Clifford's elusive "sufficient evidence" or trust in other people and sources? If the basis of knowledge is trust, who can be trusted more than God?

"The trustworthy truth of God," writes Pope Francis, is God's "own faithful presence throughout history" (LF 23). God has always been true to his promises; it is we who are blown hither and yon by the changing fortunes of time and our own whimsical desires.

It must be added immediately that trust in God's truth comes at a cost. Knowing religious truth is not a spectator sport. It involves one in a relationship with God, a relationship that is transforming.

ENDURING RELATIONSHIP

This relationship is called love. Faith and love go together like hand in glove. Faith is not a fleeting emotion, but a relationship that endures and transforms. This is a challenge to we who live in a society where relationships are disposable and where faith is reduced to a subjective preference.

When we are transformed, however, we don't get to pick our spots. Transformation comes upon a person like a hurricane, an unwanted turmoil that scatters one's best-laid plans far and wide.

Such transformation puts our trust to the test. Can trust in God endure the trauma of unwanted, catastrophic upheaval?

WHEN THE STORM HITS

There is no sense trying to answer that question before the storm hits. The only certainty is that one will be blown about in totally unanticipated ways. It is only in transformation that one will know the extent to which one is open to God's love.

Pope Francis says love needs truth. Love without truth is fickle and self-centred; it is not love at all.

Truth, however, also needs love. "Without love, truth becomes cold, impersonal and oppressive for people's day-to-day lives" (LF 27). Love is a source of knowledge. If one never desired truth, one would never come to know it.

Truth and the person who knows truth do not stand apart, indifferent to each other. The person is drawn by the beauty of truth into a relationship. Relationship is what changes us, and the relationship with God is the most transforming of all.