Are logical arguments evidence?

It is said that an argument will convince a reasonable man, and a proof will convince even an unreasonable man. So why do so-called atheists insist upon evidence? In a previous discussion, a claim was made that logical arguments are not evidence. Here I want to unpick that comment and see if we can find a way of thinking about the relationship between evidence and logical arguments that is helpful.

First I want to draw a distinction between two different types of evidence. First there is physical-evidence. This would be material stuff, such as bullet shells, exit wounds, DNA, photographs, lab results, etc. All of these would be available, either directly or indirectly to the five senses.

I take it that it was this type of evidence that was meant by the claim logical arguments are not evidence – that is, physical-evidence. Such as an arrowhead in cave can be said to be evidence for human habitation of that cave. Or that a shivering of a body can be said to be evidence it is cold.

What is troubling is that if physical-evidence is a necessary for knowledge, then we should know nothing of moral truths, aesthetic values, and meta-physical intuitions. Yet surly we do know that torturing babies is wrong, open graves are macabre, waterfalls are sublime, that the past is objective and other minds do exist. The Achilles heal of this particular epistemological theory is it is self-referentially incoherent. If its reasonable, then its unreasonable by its own merits. For no physical evidence is able to to reveal that evidence is required for reasonable belief. If it could be rationally affirmed and were true, then the Christian would be in an awkward position, for a further implication would be there is no hope for reasonable belief in non-physical entities. In fact the criteria, if adopted, would rule out the possibility of attaining reasonable belief in non-physical entities before any discussion or debate began.

There must therefore be something terribly wrong then with the criteria. Which is why I’d like to draw our attention to another type of evidence called argument-evidence. Evidence is broadly speaking that which lends support to a proposition or claim. Argument-evidence is any reason given for believing something is true or false. That is not to say that all argument-evidence is good evidence. That is just to say that arguments can count as evidence, in that they too give support for believing some proposition or claim. There can of course be counter-evidence that could dissuade belief.

For those not inclined to accept this distinction I have drawn between and physical-evidence and argument-evidence, and those who disagree with me that arguments can count as evidence, it will be useful to consider the following.

Physical evidence doesn’t speak. That is to say, all physical-evidence passes through the filter of an interpretative lens, and, perhaps unnoticed by the advocate, acquires certain meaning that was not intrinsic to the object or event itself. More colloquially, material objects have no voice to tell you what they signify. Everything is interpreted by a person who brings with them additional premises from their world view and store of experiences.

We have all gone through what its like to say one thing, and for two people to hear totally different things. A fossil will tell a paleontologist one thing. The same fossil will tell the next paleontologist another thing – sometimes even used to support mutually exclusive theories. Yet if physical-evidence was all there was available for investigation, how is it then that disparate theories can arise over the same object or event?

What happens is that somewhere between an objects discovery and its interpretation additional premises are added. These premises combine to form arguments. One hopes of course that these arguments are logical. Different premises given by different perspectives lead to different conclusions. Thus, in a way, all evidence is argument-evidence, for the physical-evidence, if left to itself, remains silent and tells us nothing.

Together for the Gospel (T4G) Conference (Day Two)

Here are the videos from the main sessions on day two of the conference (Chris Gatihi at Pilgrim in Conflict has helpfully posted notes on each of the sessions as well).

Session 4: Thabiti Anyabwile — ‘Fine-Sounding Arguments’ — How Wrongly ‘Engaging the Culture’ Adjusts the Gospel

Colossians 1:24-3:4

  • Paul’s Purpose (1:24 – 2:5)
  • Paul’s Philosophy (2:6-2:15)
  • Paul’s Practices (2:16-2:23)
  • Paul’s Perspective (3:1-4)


Session 5: John MacArthur — The Theology of Sleep! (Mark 4)

Mark 4

How do we approach evangelism?:

  • Humility
  • Obedience (Mark 4:21-22)
  • Diligently (Mark 4:23-25)
  • Confidence (Mark 4:30-32)


Session 6: John Piper — Did Jesus Preach the Gospel of Evangelicalism?

Video to come.

Full manuscript available on the Desiring God website here.

Luke 18: 9-14

– Did Paul Get Jesus Right?

– Aspects of the Pharisee’s Righteousness in Luke 18: 9-14

  • Moral
  • Religious
  • A Gift from God

– Only One Thing Missing:

– Jesus: God’s Righteous One

– Implications:

Implication 1: Jesus’ Gospel Is Also Paul’s
Implication 2: Nothing We Do Is Basis for God’s Acceptance
Implication 3: Our Standing with God Is Based on Jesus, Not Us
Implication 4: Transformation Is the Fruit, Not Root, of Justification
Implication 5: All Our Goodness Is Evidence and Confirmation, Not Grounds
Implication 6: The Gospel Is for Every Person and Every People
Implication 7: Jesus Gets the Full Glory